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And the Best Diet is........

Anyone who spends time in the forum knows that there are many different eating plans presented and advocated on a regular basis: Paleo, Low Carb, Intermittent Fasting, Vegan, etc. 

As we search for success in our weight-loss efforts, a reasonable question is: Which Diet is the Best?

Well, I finally have the answer for you. The Best Diet for Heath and Weight Loss is (drum roll, please).........

All of them.  

OK, that was a letdown. But most of you smart MFP readers probably already knew the answer.

When people ask me if they should follow a Paleo diet, my response is "Sure". Intermittent Fasting: "Why not?". Low Carb: "you betcha".

My only negative response comes when someone tries to argue that their preferred plan is "the best" or the only way to dietary enlightenment. (And it's just plain fun to poke fun at the Paleo people). The fact is that the human body can adapt to many different dietary plans. Because there are many different types of bodies and many different cultures, there are also a number of different diet plans that folks can use to achieve success. 

As it turns out, there's a really smart guy who agrees with me, and who has determined some common characteristics that all effective nutrition plans follow. 

His name is John Berardi, expert researcher and owner of Precision Nutrition. In a recent article, Berardi described those common characteristics (I am summarizing): 

1.  They raise nutrition awareness and attention. Often the very act of committing to a program or plan causes a person to pay more attention to what they eat and to become more motivated to stick to a plan. They attribute success to the food, but it is actually because they pulled their heads out of their butts and started paying attention. 

2. They focus on food quality. A common theme is most eating plans is to focus on more whole, minimally processed foods. Quality nutrition plans do not recommend eating more junk food. 

3. They help eliminate nutrient deficiencies. Many processed foods are low in nutrients because they have been stripped out during processed. The increased emaphasis on whole foods can help correct those deficiencies and leave people feeling more rejuvenated.  

4. They help control appetite and food intake. The combination of increased attention and more satisfying, quality foods often contributes to a lower calorie intake. 

5. They promote regular exercise. Exercise can not only improve attitude and promote adherence, it can also dramatically improve the body's ability to turn the food we eat (whatever that is) into functional tissue.

So choose the eating plan that best suits you--your body, your tastes, your lifestyle. Pay less attention to the primacy of the "rules", and more the quality of the food. 

And stop annoying your family and friends by preaching about your new, super-duper "diet".  

Fasted Cardio Does NOT Enhance Fat Loss

"Fasted cardio"--i.e. performing cardiovascular exercise early in the morning on an empty stomach-- is often touted as an effective weight loss strategy. I am not sure exactly when this idea originated, but it is especially popular with bodybuilders and some personal trainers. 

On the surface, the theory seems to "make sense"--in a fasted state, blood sugar levels are lower, stored muscle glycogen tends to be lower, and you have to get your energy from somewhere, so--voila!--you tap directly into those love handles.

However, like many "common sense" recommendations for exercise and weight loss, the efficacy of "fasted cardio" is not supported by science and research.

The first reason is that, as I have stated numerous times, exercise metabolism does not exist in a vacuum. The acute changes that occur in your body in response to exercise represent only a small fraction of daily metabolism. They are not permanent and they are affected by what happens in the other 23 hours of the day. 

Research has clearly shown that the amount or percentage of fat burned during an exercise session affects fat oxidation the rest of the day. In other words, if you burn more fat during a workout, you burn less the rest of the day and vice versa (assuming equal daily calorie intake). After 24 hours, there is no difference in total fat oxidation between individuals who burned more fat during a workout and those who burned more carbohydrate. 

That alone is enough to dismiss any claimed benefits of "fasted cardio" (and the idea that "cardio burns muscle" as well).

However, if we look at the "micro" level, there is little evidence of increased fat burning as well.

Proponents of fasted cardio claim that ingestion of carbohydrates prior to exercise reduces the entry of fatty acids into the mitochondria (where fat is oxidized) and increased insulin results in less breakdown of fatty acids (lipolysis) from the tissues.

However, at least two studies have shown that, even though lipolysis was suppressed 22% after carbohydrate ingestion, there was no difference in fat oxdiation compared to those exercising in a "fasted state".

Another issue is the source of the fatty acids used during exercise. Muscle cells store droplets of lipids, called intramuscular triglycerides (IMTG). While stored adipose tissue may be "mobilized" during exercise, it is the IMTG that provide the majority of the fat that is actually used--up to 80% in trained individuals. 

What that means is that during exercise, even in a fasted state, the body uses already-available stored fat in the muscles as the primary source of fat, NOT subcutaneous stored body fat.  Body fat stores are affected primarily by daily energy balance. 

What the research literature and science DOES support that, indirectly, exercising in a fasted state can impair fat loss, not facilitate it. Studies on preexercise feedings show that performance is impaired--especially for higher-intensity exercise--when one is in a hypoglycemic state. Lower intensity often means fewer calories burned, both during and after a workout. 

Other studies have suggested that ingesting a mixed carbohydrate/protein beverage before exercise results in a higher post-exercise oxygen consumption--after both low-intensity and high-intensity workouts. 

Despite the persistent popularity of "fasted cardio", the evidence clearly shows that it is not the best strategy, either for fat loss or training quality.  

Now, there are many people who prefer exercising in a fasted state and feel that it improves their performance. Let's look at some of the possible reasons: 

1. Many people say food makes them nauseous. This can be a legitimate reason, but it has nothing to do with the topic of "fat burning" or performance. It is always brought up in the discussion, but it is really irrelevant. I will say that there might be some disagreement about what constitutes "pre exercise feeding". We're not talking about a Grand Slam breakfast--a snack or replacement beverage of 100-200 calories is the "feeding".

2. Typical workouts are not that long or high in duration. Most of the studies I have read that study the effects of "fasted vs fed" feature workouts that are 60-120 min in length.  The average 30-45 min morning workout is likely not long enough or hard enough to really tax your energy stores. So, one is not likely to see much of an effect one way or another. 

3. Hard to prove a negative. If someone always exercises in a fasted state, they may not know what they are missing.

Especially based on #2, it is probably not that important who prefers to exercise in a fasted state to change their routine.

However, people should not exercise in a fasted state out of the misguided idea that it is better for fat loss.  

 

Does Delayed Onset Muscle Soreness mean a good workout?

Delayed onset muscle soreness (DOMS) is something that most exercisers have experienced. DOMS is usually associated with new activity, especially vigorous activity. The exact cause of DOMS is not completely known, but the current consensus is that DOMS is caused by an inflammatory response to microscopic tears to connective tissue in the muscles. The response is a combination of edema, increased sensitivity of nerve receptors, increased pain signals, and a disruption of cellular structure.

 DOMS is usually associated with a new type of training stimulus, not necessarily a heavy or more intense load. Eccentric loading of muscles seems to result in a greater DOMS effective, although it can be caused by concentric contractions as well. DOMS is usually noticed 6-8 hours after a workout and is said to peak 48 hours after exercise (although there is wide variability--for many beginners DOMS remains at a peak level 72-96 hours after exercise). As one repeats a certain movement or load, DOMS response reduces significantly or can disappear altogether. 

Because DOMS usually occurs after a new movement or routine, many exercisers conclude that the new movement is "better" than what they were doing before. Some people become concerned when they no longer experience DOMS after a workout, wondering if that workout is still effective. 

Because of the perception that "soreness = good workout" some exercisers actively try to do workouts that elicit DOMS. Tom Venuto has said on a number of occasions that he doesn't feel he had a quality workout unless he is extra sore the next day and feels it is a psychological boost. (I must also emphasize that Venuto is clear that this is his personal preference, not a general recommendation--his writing on the subject is thorough, balanced, and science-based).

 Is DOMS a valid indicator of progress and a quality workout? Brad Schoenfeld and Bret Contreras explored this issue for the National Strength and Conditioning Association Journal. They explored two questions: 1) is Exercise Induced Muscle Damage (EIMD) beneficial for increased training effects and 2) is DOMS a valid indicator that EIMD has occurred? 

The article reviews the literature and points out that there is indirect support that EIMD promotes muscle hypertrophy. On a "micro" level, there are a number of responses to EIMD--increases is protein synthesis, increase in stem cells, increased cellular signaling--that are associated with muscle hypertrophy.  So, "theoretically", it seems possible that, at least when it comes to muscle hypertrophy, eliciting a EIMD response might have some benefit. 

However, as with many exercise topics, saying that something is plausible or "makes sense" does NOT constitute "proof". As of yet, there is no research that supports a direct cause and effect relationship between EIMD and muscle growth. In other words, it cannot be established that these cellular responses occur specifically for the purpose of promoting muscle growth, or if they are just coincidental and can also be elicited by other types of training. It HAS been shown that hypertrophy can occur without EIMD, so it there was any effect, it would likely be more additive than absolutely necessary. In some cases, excessive EIMD can actually hinder training--reducing force production, negatively affecting form, and extending recovery time.  

As for the question "Is DOMS a valid indicator of muscle growth", the authors are much more skeptical. While there is some suggestion that EIMD might enhance muscle hypertrophy and that DOMS is a byproduct of EIMD, there is considerable variability in the DOMS response. 

MRIs have shown that symptoms of DOMS do not correlate well to the appearance of edema.  Humans can experience symptoms of DOMS without any inflammation and there is wide interpersonal variability in the occurance of DOMS following exercise. And, finally, there are types of resistance movements that have been shown to enhance hypertrophy that elicit no DOMS response whatsover. 

In summary, the authors concluded that, while there might be some justification for seeking to achieve some EIMD during training in order to maximize hypertrophy gains, the applicabilty of using DOMS to assess workout quality was inherently limited and DOMS should not be used for that purpose. 

The Final Nail in the HIIT EPOC Coffin

After an exercise workout is completed, oxygen uptake (VO2) remains elevated for some time over resting levels. This phenomenon is called, straightforwardly enough, "Elevated Post-exercise Oxygen Consumption" or EPOC. The duration and total amount of EPOC varies according to the duration and intensity of the workout. The increased VO2 means a increase in calories burned after the workout as well.

A frequent rationale for promoting High Intensity Interval Training (HIIT) programs for weight loss is the assertion that HIIT workouts burn more calories for an extended time AFTER the workout. A perfunctory use of the Google will quickly uncover dozens of examples of these claims:

"HIIT increases EPOC (excess post-exercise oxygen consumption) resulting in an elevated fat loss state for up to 24 hours after you finish your workout – something you won’t get from lower intensity exercise."

And another:

"Long, slow, low-intensity cardio will produce a small EPOC effect that will at best, last only a couple of hours after the workout. Basically the 400 calories you burn during the workout will be all that you burn, because the EPOC effect afterwards is negligible. However, studies have shown that after HIIT workouts, the EPOC effect can still be found up to 38 hours after the workout - basically your body is burning fat to fuel the restorative processes for 38 hours AFTER your workout! So, even though you may have only burned 250 calories during your HIIT workout, the total calories burned after will be far greater.  Those calories, plus the 250 burned during the HIIT workout surpasses the 400 burned during the slow, steady-state workout by a LONG, LONG way."

Actually, the "studies" point out that these claims are exaggerated, to say the least, and that the effect of EPOC for all workouts is modest at best. There are plenty of good reasons to include HIIT workouts in your routine, but a supposedly elevated EPOC is not one of them. 

A 2006 study reviewed all the research that had been done up to that time on EPOC. The authors concluded that the additional calories burned from EPOC for endurance exercise was about 7% of total calories expended during the workout. Calories from EPOC for HIIT workouts were almost double, approximately 13% of total calories during the workout.

LaForgia J et. al. Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. J Sports Sci. 2006 Dec;24(12):1247-64.

Double the calories sounds pretty good, however, when comparing the effects of something like EPOC, one must look at the TOTAL calories burned, not the percentage increase and not the "duration" of the "afterburn". Looking at the actual numbers tells a different story.

80 kg individual does a 60 min endurance workout and burns 640 calories. Add 45 calories for the 7% EPOC for a total of 685.

Same person does a 20 min HIIT workout and burns about 300 calories. Even with the extra EPOC of 13%, that's only an extra 40 calories, for a total of 340.

There is no "afterburn" that is going to make up those extra 300 calories.

(For a more in-depth discussion of the LaForgia study, see Lyle McDonald's excellent review: 

http://www.bodyrecomposition.com/research-review/research-review-effects-of-exercise-intensity-and-duration-on-the-excess-post-exercise-oxygen-consumption.html)

More evidence was presented in a recent article on the website of the National Strength and Conditioning Association. Several studies were reviewed (including the LaForgia study already discussed) and showed that, even when EPOC remains elevated for 9 hours following a HIIT workout, total calories burned from EPOC only ranged from 18 to 80 calories TOTAL. The only exception was a recent study from Appalachian State University that reported a total EPOC of 190 calories over 14 hours).

As if that weren't enough, a review article published by Melanson et al in 2009 showed that exercise training does not affect 24 hour total body fat oxidation, even though it increases fat metabolism in muscle.

Exerc Sport Sci Rev. 2009 April ; 37(2): 93–101. doi:10.1097/JES.0b013e31819c2f0b.

Other studies have shown either no difference in the 24-hr rate of fat use following exercise, regardless of intensity, or, even when there was a small increase in fat oxidation following high-intensity exercise, the total amount of fat burned was trivial.

The conclusion of the NSCA article was that research:

"...suggests that EPOC is not a primary contributor to the energy cost of exercise and that it does not alter substrate use enough to be of consequence in a weight loss program."

Again, the purpose of this is not to denigrate HIIT workouts. They can play an important role in many workout programs, and, when the time comes, they are essential in order to accomplish significant body recomposition. However, like so much else in the fitness world, the benefits of HIIT are sometimes overhyped and their application frequently overgeneralized. People need different types of workouts depending on their age, body fat levels, fitness level, fitness experience and overall health. When starting a weight loss program, total energy expenditure is still a primary goal of the exercise component. Endurance cardio workouts, submaximal interval workouts, and even endurance strength workouts are usually the better choices for beginners.

"Useless Cardio"? Try Tempo Training

These days, cardiovascular training is getting a bad rap. Some of it comes from the usual cyclical swing of exercise preferences (most proponents of HIIT today don't know that endurance cardio training became popular 40 years ago as a reaction to the overuse of HIIT training during the 1960s), some of it is due to new research which has popularized the long-known benefits of high-intensity training, but it also comes from the fact that many people actually DO large volumes of low-level cardio without sufficient focus and without incorporating other elements into their training. 

However, there IS a form of cardio training that is anything but "mindless" and can kick your program into a higher gear. Between "endurance cardio" and "HIIT" is a form of cardiovascular training that can dramatically increase fitness performance--and can burn a bucketload of calories to boot. 

It's called "tempo training", and it should be part of your training routine. It is mostly associated with running, but can be adapted to most cardio routines. 

Tempo training has been the cornerstone of my workouts for almost 40 years. It was something I learned intuitively in my running days, years before I went back to school to study exercise physiology. I always enjoyed running, and I enjoyed running hard and fast, so I often pushed the pace during my training runs. I found that these hard runs seemed to result in a lot more improvement than even my interval training. 

What is tempo training? It means working at an intensity that is "hard, but sustainable". Not all out, but a pace that is right on the edge and that requires that you stay completely "in the moment"--monitoring pace, breathing, keeping stride relaxed, etc. Sometimes when I am doing one of these workouts indoors, I lose track of everything -- the game on TV, the music on the iPod -- but the workout. 

And it means sustaining this intensity for a longer period of time--a continuous 20 min for example, or a series of longer intervals with shorter recovery times. 

How does tempo training work? A quote from a 2007 Runners World describes the physiology: 

[quote]Tempo running improves a crucial physiological variable for running success: our metabolic fitness. "Most runners have trained their cardiovascular system to deliver oxygen to the muscles," says exercise scientist Bill Pierce, chair of the health and exercise science department at Furman University in South Carolina, "but they haven't trained their bodies to use that oxygen once it arrives. Tempo runs do just that by teaching the body to use oxygen for metabolism more efficiently."

How? By increasing your lactate threshold (LT), or the point at which the body fatigues at a certain pace. During tempo runs, lactate and hydrogen ions--by-products of metabolism--are released into the muscles, says 2:46 marathoner Carwyn Sharp, Ph.D., an exercise scientist who works with NASA. The ions make the muscles acidic, eventually leading to fatigue. The better trained you become, the higher you push your "threshold," meaning your muscles become better at using these byproducts. The result is less-acidic muscles (that is, muscles that haven't reached their new "threshold"), so they keep on contracting, letting you run farther and faster.[/quote]

In an even older article in Runners World in the late 1970s, they describe tempo training as "aerobic, but delivering energy aerobically at a faster rate", While that might not be precisely correct, I always felt it was a good, simple description. 

For runners, a tempo pace would be approximately 30-40 sec/mile slower than recent 5K pace, or 15-20 sec/mile slowerthan 10K pace. For non-runners, heart rate will be around 85%-90% of HRmax, breathing should allow you to give a brief (2-3 word) answer to a simple question, but not carry on a conversation (or even pay attention to one). 

To build this into your routine, you can start with 5x3 min intervals with 60 seconds recovery (exercising, not rest) in between. Build this up until you can do 20 min continuously.

You can also do some "narrow intervals" where you keep a high average tempo, but change the workload up and down within a narrow range to give youself a little mental break. For example, today I alternated 2 min at 7.2-7.4 mph running with 60-90 sec of running at 6.8 mph--just enough to take the edge off and let me maintain the effort longer. 

What specific advantages does tempo training provide over some other types of cardio training? For one, you can burn 20% more calories than you would for a comparable endurance cardio workout. Because of the higher intensity/duration, there is a bit of an "afterburn" -- extra calories burned during recovery. And you will experience notable increases in fitness level--which will allow you to sustain a higher workload during your other workouts and burn more calories during those as well. 

I also think that many people are doing what they think is HIIT, but is not really. To get the most benefit from a HIIT workout, you have to go "all out" during the work intervals. Otherwise, you are just doing a very short interval workout. A lot of people THINK they are going "all out" but they are often only at a 80%-85% effort--which is great, but which is not necessary going to provide the level of benefit they are expecting. Not everyone--and especially not beginning exercisers-- is capable of working at 100% of max, despite their motivation and dedication. 
 
Like all good things, with tempo training, more is not better. High tempo workouts put more stress and strain on joints and can push you into a state of overtraining if performed too often. Twice a week is more than suffiicient for this type of workout.  

Tempo training results in a high calorie burn, great conditioning, and even a little EPOC, while being (IMO) more accessible and attainable for beginners to advanced beginners than all-out HIIT. Before you completely ditch cardio, give it a try and you might be pleasantly surprised at the results. 

Heavy Lifting Always the Best?

In recent years, "lifting heavy" has become a ubiquitous exercise recommendation, often without regard to the background of the individual seeking advice. 

And, make no mistake, there are many benefits to lifting heavier weights. 

However, "lifting heavy" might not be the best choice for everyone all the time. Many people who come to MFP are carrying a lot of extra weight and are just starting an exercise program. In addition, others might have physical or medical issues that contraindicate "lifting heavy". 

A case can be made that for these individuals, lifting a higher volume of lighter weights is a more effective way to start, and that the choice of modality (e.g. free weights vs machines) is not that important. 

Before I proceed, here is my usual disclaimer: I am NOT saying this is the "best" approach for "everyone" and I am not dismissing anyone's successful personal anecdote. As a fitness professional, my job in writing for a general audience is to present evidence and recommendations that can be a "best fit" for certain groups. 

Also keep in mind that lifting "lighter" weights does not mean during arm curls with 5lb dumbbells. It still means working to "failure" -- just in 12-20 reps rather than, say 4-6. 

There is a lot of research to support this idea, but for this article, I am relying on three sources: 

1. AEROBIC, ANAEROBIC, AND EXCESS POSTEXERCISE OXYGEN CONSUMPTION ENERGY EXPENDITURE OF MUSCULAR ENDURANCE AND STRENGTH: 1-SET OF BENCH PRESS TO MUSCULAR FATIGUE
CB Scott et al, Journal of Strength and Conditioning Research 2011 Vol: 25(4) 903-908. 

2. MECHANICAL LOAD AND PHYSIOLOGICAL RESPONSES OF FOUR DIFFERENT RESISTANCE TRAINING METHODS IN BENCH PRESS EXERCISE
Sebastian Buitrago et al, Journal of Strength and Conditioning Research 2013 Apr 27(4) 1091-1100

3. TRAINING THE OBESE BEGINNER, PART 3: http://www.bodyrecomposition.com/fat-loss/training-the-obese-beginner-part-3.html Lyle McDonald

Let's look at some specific reasons why lifting lighter weights can be a good choice for overweight beginners: 

1. They don't need to increase muscle mass. The idea that "lifting heavy increases muscles that burn more fat at rest" is one of the most common mantras repeated on MFP. 

However, someone who is significantly overweight (i.e. BMI >34, 35%+ BF for men, 40%+ for women), often has a lot of muscle mass already. They don't need more. They might gain more as a result of training, or they might lose some muscle mass as their bodies "resize" themselves over time. In either case, pushing overweight beginners to "increase muscle mass" is usually not a productive goal--at first. 

2. Lifting heavy doesn't result in any more afterburn. At least not in the types of workouts that beginners are likely to follow. Both studies cited above compared lifting as various intensities, ranging from 37% of 1 RM max to 90% 1 RM max. Surprisingly, there was no difference in Elevated Post Oxygen Consumption (EPOC) between any of the different intensities. This is different than the model that occurs during aerobic exercise, where EPOC is directly relation to duration and exponentially related to intensity of exercise. 

3. Total energy expenditure is significantly higher during lighter-weight training. This effect was seen in both studies. This makes sense when you realize that, at lighter weights, exercise time is significantly increased and rest times are greatly minimized. 

Dr Scott summarizes: 

[quote]Our data indicate that a single set of muscular endurance-type lifting to fatigue expends more total energy than a single set of strengthtype lifting to fatigue; this apparently is related to the amount of work performed within the set.[/quote]

4. Higher volumes of lighter-intensity lifting can enhance whole-body glycogen depletion. People who are significantly overweight usually have an impaired ability to oxidize fat. It is not fully known whether this impaired ability is a CAUSE of gaining weight, or an EFFECT of gaining weight, but the condition exists. They have plenty of available circulating fats, but are inefficient at using them (as opposed to those who are at lower levels of body fat--in that case, the problem is usually more with fat *mobilization* vs fat oxidation). 

Two effective ways to enhance fat oxidation are: reducing body fat by maintaining a sustained caloric deficit and depleting muscle glycogen. Performing a high(er) volume of lifting can enhance that effort. 

5. Psychological reinforcement and increased confidence. Which workout do you think is going to encourage someone to come back: a heavy workout that leaves someone feeling discouraged and sore, or one that leaves them feeling energized and with a feeling of success? 

I believe that it is important for beginners to finish each workout with a feeling of success and accomplishment; to see incremental gains each day. 

Lyle McDonald mentions that overweight beginners often don't have the endurance or the fitness level to burn large amounts of calories during an aerobic workout. With the other changes that take place at the beginning of a weight-loss program, progress can seem excruciatingly slow. 

I think that the effects of resistance training have a much faster and more substantial "real life" impact. Even without weight loss, people feel more confident, more positive about themselves, and have greater compliance when they feel stronger. 

So what are the specfics: 

1. First of all, whether you lift light or heavy or in-between, it is important to work to momentary "exhaustion", regardless of # of reps or time of set. 

2. By "lighter", I am referring to an intensity of 50%-55% of 1 RM. This means about 15-20 reps per set. Work up to 3 sets per exercise. 

3. The movements should be controlled--not "super slow", but not super fast, either. The set should last at least 45 seconds. 

4. As usual, work large muscle groups. Leg press, squat, chest, lats, shoulders. Don't bother with small-muscle isolation exercises right now. 

5. To start, any modality can be effective--machines, cables, or free weights. Yes, free weights are better in the long run, but you don't need to be a "purist" right now. 

6. At these weights, you don't need any more than 60 seconds recovery between sets. Better yet, alternate upper/lower, push/pull exercises rather than sitting there waiting 60 seconds. 

7. You really only need to lift 2 times per week. 

Again, I am not trying to say this is the "best" way to lift. But heavy lifting is not for everyone, and may not be the best choice for anyone just starting out. Given today's fitness climate, it could be easy for someone starting out to get the impression that doing anything other than heavy lifting is pointless. That is not true. 

Ultimately, after several weeks or months on this routine, you will probably get better results by moving up to a heavier weights and a more aggressive program. Some beginners will want to just dive right in and start pushing iron. That's OK, too. 

But if you are not ready for that yet, or if you have some physical issues that preclude you from lifting heavier weights, take heart that there are alternatives that can be very effective at helping you reach your weight-loss goals. 

Does "Machine X" REALLY burn more calories than a treadmill? NO, NO, NO, NO, NO

Losing weight is probably the #1 reason why people start exercise programs. Equipment manufacturers know this.

If you are selling a new type of exercise equipment, the best way to attract attention from potential buyers is to claim that your product "burns more calories" than any other piece of equipment. Especially if that equipment has a unique design or movement and is only available from limited sources (i.e. an infomercial).

The fact is, however, that calories burned during exercise depends on only two factors: Body weight and intensity.

(Note: for the purposes of this discussion, I am going to stick to cardiovascular exercise and stay out of the chum of claims about resistance exercise, HIIT, etc).

The intensity of an exercise (and thus the rate of calories burned) depends on the amount of oxygen required to fuel that particular movement intensity. As the exercise workload increases, there is a greater need for energy, and thus oxygen uptake increases. When oxygen uptake increases, more calories are expended.

It's that simple.

If someone is exercising at a given intensity--i.e. a given oxygen uptake--they will burn the same amount of calories no matter what the exercise activity. Running, swimming, cycling, climbing stairs, an elliptical, etc, etc.--it makes no difference.

It is physiologically impossible to work at the same intensity (oxygen uptake level) on two different machines and have a higher calorie burn on one machine over the other.

If any commercial claims that '"Machine X" burns 3 times the calories as a treadmill"', they are lying by not telling the whole truth. They are not comparing equal workloads.

So, in principle, it is possible to burn calories at an equal rate no matter what kind of cardio you are doing, as long as you are working at the same intensity (i.e. oxygen uptake).

In reality, there are some differences. The nature of some movements is such that it is easier and more comfortable for people with less experience to work at a higher intensity.

In studies where subjects choose the exercise workload based on perceived exertion, the subjects worked at a higher absolute intensity (oxygen uptake) when running or working on an ARC Trainer as compared to a bike or stairclimber. That makes sense given that running or doing an elliptical uses more muscles, features more dynamic movements, or includes a bounding movement. Activities such as cycling or stairclimbing focus the effort on fewer muscles and so beginners often experience localized muscle fatigue and this limits the effort at first.

But while some exercises may "feel harder" at first and result in lower exercise intensities, the difference can be made up over time. It may take a little longer to learn the techniques and increase muscle endurance for activities such as cycling and swimming, but people trained at those activities can achieve similar intensities and calorie burns as any other execise modality.

As always, there are two principles at work here.

One: there are no "magic bullets". There is no "secret" form of exercise that provides unique results that cannot be achieved any other way.

Two: WHAT you do for your exercise is not nearly as important as HOW you do it.

Don't be fooled by deceptive marketing hype. If you see a product and decide you like the exercise and will want to work out using that equipment, then by all means, go for it. But don't choose any exercise activity based on overstated claims of "unique" properties and "magic" calorie burns that can't be achieved any other way.

Exercise Calories: sometimes the cardio machines ARE more accurate

For once and for all, I am going to write this all down.

For those who don’t want to read the whole thing this is the summary:

  1. Machines and HRMs calculate calories differently.
  2. HRMs do not measure calories directly.
  3. For some exercises, machines can actually be the more accurate number.
  4. HRM accuracy depends greatly on the accuracy of the user setup information.
  5. HRM are only accurate (such as they are) under very specific exercise conditions, i.e. steady-state cardio exercise. Just because an HRM displays a number doesn’t mean the number has any value.
  6. HRM accuracy can also be affected by a number of other factors.

Estimating calories burned during exercise is of primary interest to most people who are trying to lose weight. There are three main sources of exercise calorie information:

  1. Calorie readouts on machines.
  2. Calorie estimating feature on Heart Rate Monitors (HRMs)
  3. Data tables (such as MFP)

I have addressed #3 in another blog, so I am going to focus on #1 and #2.

The “conventional wisdom” is that “machines cannot be believed” and “HRMs are always the most accurate”. Neither of these statements is completely true. It IS true that cardio machines and HRMs estimate calories in fundamentally different ways.

Before we look at that in more detail, let’s make sure everyone is on the same page.

During aerobic exercise, the rate at which calories are expended is a product of two factors:

INTENSITY x BODY WEIGHT

That’s it. (Factors like age, height, and gender are necessary for heart rate monitor estimates, but those factors are only needed for HRMs, as will be explained later).

So: more intense workloads will burn more calories than less intense workloads and, at any given workload, heavier people will burn more calories than lighter people.

Next: the energy cost for any given exercise workload is relatively fixed. For example the energy cost of walking at 3.0 mph and 5% elevation on a treadmill (w/out holding on) is approximately 5.4 METs (a MET is a measure of aerobic intensity. That 5.4 MET intensity is the same for everyone—regardless of age, gender, or fitness level.

So, every given speed, elevation, watt level, etc, has a relatively fixed energy cost. If we can measure the workload, and we have formulae that can accurately calculate the energy cost for a given workload, it is straightforward arithmetic to determine the calories expended.

Machines
Most modern commercial cardiovascular equipment uses computer chips to control the operation of the equipment. The digital control means that exercise workloads can be accurately measured.

For simple movements, such as treadmill walking and running, or stationary cycling, there are longstanding, validated equations for estimating energy expenditure.

Since these machines can accurately measure workload intensity, and since they are programmed with accurate equations for estimating calorie expenditure, all they need is body weight to calculate exercise calories. So, for stationary cycling and treadmill walking (w/out holding on), as long as you enter body weight, the machine readings should be accurate—or at least as accurate as any indirect estimate can be. (It’s a little different for running—not only do you have differences between treadmill running and outdoor running, research I have seen suggests that, starting with speeds above 6.5 mph, the actual energy estimate equation itself starts to overestimate calories—so treadmill running calories are likely 10%-25% high).

Elliptical cross trainers are a different story. While the machines can consistently measure a work output, there is no consistent movement design for cross trainers. Each manufacturer’s equipment is different. Therefore, there is no one validated equation that can be applied to all cross trainers. Each manufacturer can program the machine any way they want. The only way to have an accurate calorie estimate for a cross trainer is for the manufacturer to develop and validate their own custom algorithm for each machine—that is expensive and time-consuming. As I have mentioned before, the only company I know that has even tried to do this is Life Fitness, and they have only done it on a select few models. So, in the case of elliptical, it is best to assume that NONE of them are particularly accurate.

It is important to repeat that cardio machines estimate calories differently than HRMs—they measure the actual workload being performed and use that for the estimates. The accuracy of the machine readings depends on the following factors:

  1. How accurately the machine can measure actual exercise workload
  2. Does the machine allow user to input weight?
  3. How valid are the equations programmed into the machine?

Based on these factors, treadmill walking and stationary cycle calorie estimates should be pretty accurate, running off by up to 25% (my estimate), and elliptical cross trainers – who knows? (Stairmasters could be fairly accurate, but their equations are based on not holding on at all and I know very few people who do that).

Heart Rate Monitors

Heart Rate Monitors estimate calories by a completely different method than machines. It is important to emphasize up front that HRMs do not “measure” calories—they don’t have any special sensors or anything. In fact, the ONLY thing that HRMs measure is heart rate. That’s it—the calorie function is just a very indirect estimate.

How do HRMs estimate calories? They use algorithms based on the relationship between heart rate and oxygen uptake (VO2). It’s increased oxygen uptake that is actually responsible for increased calorie burn.

During steady-state cardiovascular exercise, there is a relatively fixed relationship between heart rate and VO2. An increase in workload requires an increase in VO2 which leads to an increase in heart rate. (A decrease in workload has the opposite effect). We know some approximate relationships between HR levels and VO2 level—e.g. 70% of HRmax is equal to 57% of VO2 max, 85% of HRmax is equal to 70% VO2max, etc.

Put very simply—if we know a person’s HRmax, HRrest, and VO2max, the individual “scale” for that person can be established. If the VO2max is 40, and we know the heart rate is 85% of HRmax, and we know that 85% HRmax = 70% VO2max, then we can calculate that the exercise workload is 28 (70% x 40), and that, along with body weight, allows us to calculate calories.

HRM manufacturers create algorithms that attempt to capture and refine this relationship, as well as make the algorithm applicable to the widest range of individuals. They validate the algorithms by taking a group of subjects and comparing the VO2/calorie expenditure predicted by the algorithm to actual VO2 measurements taken with a metabolic cart. It is in the generation of these algorithms that factors such as age, gender, and height, for example, are necessary factors to improve accuracy (don’t ask me why—I am NOT a mathematician or statistician).

It must be pointed out that this method is very much based on RELATIVE intensities rather than fixed workloads. In other words, an exercise heart rate of 150 beats/min means absolutely nothing unless we know the context – the persons HRmax, HRrest and VO2max.

It also must be emphasized that the HRM algorithms are ONLY valid under conditions in which there is the consistent relationship between heart rate and VO2 as described above. If heart rate increases without an increase in VO2, then the calorie numbers are bogus. REMEMBER: HRMs do not measure calories—they estimate calorie burn under very specific circumstances.

The accuracy of HRM calorie estimates depends on these factors:
  1. Accuracy/quality of the algorithms programmed into the device (these are usually proprietary for each manufacturer).
  2. Accuracy of the user setup information
  3. How closely the exercise activity matches the research conditions under which the calorie counting algorithms were developed (i.e. steady-state cardiovascular exercise).

As you can see, there is no single answer as to which method is “most accurate”.

For simple activities, such as treadmill walking, walking/running on level ground outdoors, and stationary cycling (on a quality commercial bike), the calorie displays on the machines can be quite accurate because they measure actual workload.

For activities such as cross trainers, stairclimbers and more unstructured activities like group exercise classes, walking outdoors on hilly terrain, then HRMs are likely to be more accurate.

However, if HRMs are not set up properly with accurate user data, then the accuracy of the numbers can be WAY off. Under the best of circumstances, HRMs are only about 80% accurate. Conditions such as illness, lack of sleep, hot weather, and cardiovascular drift can significantly lower HRM calorie accuracy even further.

For activities/conditions that are different that the conditions under which HRM calorie equations were developed, HRM calorie numbers are not accurate at all. These include: activities of daily living or being at rest, lifting weights, thermal stress (e.g. hot yoga).

No need to ditch the elliptical....

Is there one type of cardiovascular exercise that is better than all others? Does it make a difference what cardiovascular (aerobic) exercise you do?

 

In general, the answer is “NO”. When it comes to aerobic exercise, HOW you do it is much more important than WHAT exercise you do.

 

The primary training goal of all aerobic exercise is to improve the function of your cardiovascular system, i.e. to improve your ability to deliver oxygenated blood to the tissues where the oxygen is used to create energy. This is referred to as increasing your maximum aerobic capacity, or maximum oxygen uptake (VO2max). The higher your cardiovascular fitness level, the more oxygen your body can use to create energy via the aerobic metabolic pathways.

 

For people looking to lose weight, aerobic exercise, in addition to the training effect, contributes to maintaining a calorie deficit by burning a large number of calories at one time.

The higher your VO2max, the higher intensity you can sustain during your workouts. And the higher intensity you sustain, the more calories you will burn, since caloric burn is the direct result of workout intensity X body wt.

 

While any activity can burn calories, in order to achieve a training effect, aerobic exercise must be performed at a minimum intensity, frequency, and duration. For sustained results, the intensity needs to be at least 60% of VO2max, for 20 minutes a session, three days per week. (This is not set in stone, but is still the generally accepted guideline).

 

If the activity meets the above intensity, frequency, and duration guidelines, then ANY cardiovascular exercise will yield the same general cardiovascular training benefits. And if you are working at the same intensity level, ANY cardiovascular exercise will burn the same number of calories.

 

The idea that “doing ‘Exercise X’ burns twice the amount of calories as a treadmill” for example, is physiologically impossible. In order to “burn twice the amount of calories”, you have to be working twice as hard.

 

While hypothetically doing any aerobic exercise can result in similar fitness and weight loss benefits, there are some practical differences between aerobic exercises. There are some movements that are inherently more intense, some movements that “feel” easier when working at higher intensities, some that require more adaptation before one can work harder, and some that require a greater skill level.

 

One of the reasons why running is such an effective exercise—both for conditioning  and weight loss—is because, even at slow speeds, running is a relatively high intensity exercise. The dynamic motion of running also does not focus the effort on one small area of muscle, so musculoskeletal adaptation tends to be faster. When compared to other types of exercise, more people find that running—even though the actual intensity of effort is higher—“feels” less hard than other modes of exercise. (Results of research in which subjects self-selected intensity based on a given perceived exertion level).

 

This contrasts with activities such as cycling and stairclimbing. These activities have smaller movements, and concentrate the resistance load on a smaller muscle mass. Because of this concentration, localized muscle fatigue is usually a limiting factor for beginning exercisers rather than intensity itself. Both intensity and duration of effort are limited by muscle fatigue. As a result, the exercise—esp stair climbing—“feels” much harder, but, in fact the actual workload (oxygen uptake) is significantly less than that achieved by running.

 

Now before the cyclists and stepmillers get out the pitchforks and torches, let me emphasize that this does not mean that cycling and stairclimbing are “inferior” exercises. Far from it. It just means that when you add these activities to your routine, it takes more time to condition the muscles and to build up the strength and endurance necessary to push yourself to the same high level as running. It also means that you cannot rely on factors like muscle fatigue or sweat to evaluate the true intensity of the workout—at least not at first.

 

Another example is swimming. Swimming is an excellent conditioning exercise. However, for swimming to be most effective, one must not only build up muscle endurance, esp in the arms and shoulders, one must also take the time to develop proper stroke mechanics.

 

All of these exercise movements—cycling, stairclimbing/stepmill, swimming—can be highly effective for both cardiovascular conditioning and weight loss. They just require a little more time and dedication to develop the techniques and the movement-specific muscle conditioning and endurance necessary to achieve optimum results. This category also includes cross-country skiing and rowing.

 

Walking is an exercise that has its own limitations. Walking can be an excellent exercise because it is easy to do, safe for anyone, and requires almost nothing in the way of facilities or equipment. However, walking is inherently a low-intensity exercise. Even at speeds that most people would consider “vigorous” and close to their comfort limit – eg. 4.0-4.5 mph—walking intensity is less than 5 METs. Again, any activity is positive and burns calories. However, walking may not be intense enough for younger or fit individuals to experience a training effect—and the calorie burns are relatively low. These limitations can be offset by incline walking, vigorous arm swings (or poling), and learning race walking.

 

And then there are elliptical cross trainers. Elliptical cross trainers are somewhat of a “hybrid” activity—the dynamics of the movement often result in HR and VO2 levels similar to running, but with less impact (in fact, in another study which looked at actual VO2 achieved when subjects self-selected the workload based on perceived exertion, the Cybex Arc Trainer narrowly edged out running as the highest actual exertion level).

Elliptical cross trainers also have a large range of resistance levels. Most elliptical can be performed at very low levels—comparable to slow walking—but also have workload capacity that is beyond the practical physiological range of human beings.

 

I sometimes read remarks such as “elliptical are for grannies” or “elliptical aren’t effective because the momentum does all the work”. That may be true for some crappo infomercial piece that doesn’t have any way to increase resistance, but it’s a really unintelligent thing to say about a commercial cross trainer. Like many pieces of equipment, YOU have to supply the effort. Since commercial cross trainers have a workload capacity that exceeds human physical  ability, there is no reason why someone can’t push themselves as hard as they need or want to on an elliptical—to max effort if necessary. If someone is doing a mediocre workout on a cross trainer, it’s not the fault of the machine or the exercise—it’s the fault of the user.

 

The last part that has to be addressed when you evaluate the effectiveness of any new piece of cardio you try out is the concept of training specificity. This simply means that training effects tend to be specific to the type and manner of exercise performed. While all types of cardio result in similar GENERAL cardiovascular training effects, movement efficiency is limited more to the specific exercise you do on a regular basis. Put simply: running does not prepare your muscles for doing a Stepmill. If you always run and then one day try something like a Stepmill, you will likely struggle at first and think “man, this exercise is really kicking my but”. However that perception of being more intense is due more to localized muscle fatigue than anything else. In fact, if we were to measure your VO2, we would probably find it to be noticeably lower than when running on the treadmill at a similar level of perceived exertion. I do the Stepmill only occasionally – not enough to really condition my muscles for it—and I know that, even though my legs hurt a lot more and it is a struggle to do 15-20 min (instead of 30-40 running), my VO2 on the Stepmill is at least 20% lower than what I can sustain while running. So even though I feel like I am working harder, I am actually burning a lot fewer calories per minute. (Now, if I trained regularly on the Stepmill, I would gradually increase my leg strength and endurance for that modality, and eventually be able to reach the same VO2 on both).

 

Again, my point is NOT to downgrade ANY form of cardiovascular exercise—my position is exactly the opposite. I just think it is important to know the facts so you can make an informed judgment.

Estimating Calories: Activity Databases?

An important part of tracking energy expenditure is knowing how many calories you are burning during exercise and non-exercise activity. There are a number of tools available for this purpose: Activity Database (e.g. MFP), Machine readouts, Heart Rate Monitors, Free-living monitors such as Body Bugg. Since I have discussed HRMs in great detail in other blogs, I am going to concentrate on Activity Databases. 

A brief review: a calorie is a measure of heat. The reason we can use it to estimate energy expenditure is that the biochemical processes that occur to provide our bodies with the energy they need to function give off fixed amounts of heat. 

How do we actually measure calories? There are two most common methods used in research are: measurement of oxygen uptake through analysis of expired air, and metabolic chambers. 

Movements/exercises that are simple, rhythmic, and consistent are easier to measure, and the equations used to predict energy expenditure are more accurate. They are also easier to generalize to the population as a whole. 

Movements/exercises that are complex, intermittent, that derive energy from different metabolic pathways (i.e. anaerobic vs aerobic), and can occur under varied conditions are very difficult to measure and very diffcult to generalize. 

In addition, energy expediture is very specific to the exact level of workoad intensity--so the more general the description of the activity, the less accurate the energy estimate will be. 

Reliable energy prediction equations have been available for years for activities such as walking, running, stair climbing, and cycle ergometer (stationary bike that accurately measures workload). 

Energy estimates for other exercise activities have been derived by studying a group of subjects, measuring their oxygen uptake while performing the activity at various tempos, and then deriving a "best fit" equation that is used for everyone. The accuracy of the equation/table is dependent on the quality of the study, the size and makeup of the sample group, etc. 

There are fairly extensive lists predicting the energy cost of various recreational and occupational activties. They were developed primarily to evaluate when someone who had suffered a heart attack or job injury could return to work. These were developed using the same methods described in the previous paragraph and are subject to the same limitations. A well known example is the Taylor Codes Compendium of Physcial Activities.

(This was during those quaint, older times when A) there were still jobs available that required physical labor; B) there were still jobs available for older American workers who had suffered an injury or a heart attack.) 

Activity databases include all of the above. Therefore, some listed activities will be very accurate and some won't be accurate at all. Let's look at some typical groups of activities in a little more detail:

Walking: if you are on a treadmill at 4.2 mph or less, and you are not holding on to the handrails, then the database numbers and the machine numbers will be very accurate (assuming you can enter your body weight), both for level walking and incline walking. They should be more accurate than any other method, including at HRM or Body Bugg. (The exception would be for someone who is extremely overweight/morbidly obese). 

This holds true only if you can enter the actual speed and elevation numbers. A database entry such as "brisk walking with hills" will not be that accurate. If that is your only choice, or if you are walking outside over varied terrain, an HRM will usually be more accurate than the database (only if it is set up properly). 

Running: The equations for running are also well-established, but I have seen research that suggests that, on treadmills, and as speeds increase above 6.5 mph, they start to overestimate energy expenditure by up to 15%. So database and machine numbers should be OK with that adjustment. For outdoor running on a flat surface or a track, the database numbers should be even a little more accurate--otherwise, with varied terrain, it's the same as walking. 

Computerized (Commercial) Stationary Bike/Stepmill: The machine readouts should be pretty accurate, althougth you have to minimize handrail support on the Stepmill. Most commercial exercise bikes have calibrated resistance levels that, while not research level accurate, are accurate enough for our purposes. The problem with the databases is that they don't allow you to enter precise workloads (e.g. avg Watts)--they just use descriptions such as "light", "moderate" and "hard". In this case, I would go: machine, HRM, and use database only as a last resort. 

Cross Trainers: When it comes to calorie estimates, cross trainers have the worst reputation for accuracy--and deservedly so. It's because of the non-standard nature of the movement--every manufacturer has a different movement design, so each machine needs to have its own specific energy-prediction algorithm. Some do it better than others, but the list of cross trainers with accurate calorie readouts is very small. Database numbers are probably going to be significantly off as well, and need to be approached with caution. 

Group exercise: Energy expenditure is so dependent on coordination, skill level, willingness/ability to push oneself, choreography of the class, etc, that any database entry will be mostly a random guess. Flawed as they can be, HRMs are the best choice for these activities (keep in mind that at best an HRM will only be about 80% accurate). 

Circuit Training/CrossFit/P90X, etc: These types of activities are very difficult to predict--because of the varied movements, different metabolic pathways, etc, there is no method that will be consistently accurate--database, HRM, nothing. If this is your main form of exercise, you can use the HRM numbers as a starting point, but you will likely also have to use the "trial and error" method. 

Recreational/Occupational Activities: See "Circuit Training" ---only worse. The extra problem with using tables for these types of activities is that they often assume you are doing the activity continuously at a consistent pace. If you put down "gardening, 2 hours" you will get a huge number. If we did a time-study of you doing the activity, we would likely find that in 2 hours, you did only 30 minutes of the sustained "gardening" activity on which the database numbers were based. I would be extremely cautious and conservative about entering ANY recreational/occupational activities into your daily energy estimates. 

Hopefully, I didn't wander too far off the path here (what's the calorie burn for "rambling on"?), but gave you some perspective on how you can rely on different sources for calorie numbers. 

If you see big discrepancies--between MFP and the machine, between MFP and your HRM, the machine and your HRM, etc--consider the nature of the activity and whether it falls into one of the "more accurate" or "less accurate" categories described above. That will help you make a better "educated guess" on how to include those numbers. 

Consider the nature of the activity (simple & consistent or varied & intermittent?)

Can you enter in precise workloads? (speed/elevation, watts, distance/time)? 

Is the activity mainly aerobic, anaerobic, or a combination? 

Is your effort dependent on mastering specific sport skills? 

How continuous is the activity movement? Is it a sustained effort or intermittent? 

This will help you determine the most accurate source of calorie information. 
 
A general rule is that the more "general" the estimate, the more caution you should exercise when including those numbers in your eating plan.  



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