My comments: In the last year or three, exercise programs for fat loss such as Alwyn Cosgrove's Afterburn, Craig Ballantyne's Turbulence Training and others have been geared around the concept of using certain types of training (either interval style cardio or highish rep/short rest weight training) to cause fat loss through an 'afterburn' effect where calories are burned after workouts to a greater degree than following standard training styles (esp. low intensity cardio). There's little to no doubt that these programs work (I'll come back to this at the end of the review) but this review paper raises the issue of how significant an impact the post-exercise calorie burn (called EPOC which stands for excess post-exercise oxygen consumption) actually is under most circumstances.

The first topic discussed is what EPOC actually represents. An outdated concept is that the post-exercise calorie burn represented an 'oxygen debt' representing the difference between what the body needed and what was available, this turns out to be simplistic and wrong. Lactate metabolism, phosphate resynthesis and fatty acid cycling, along with increases in catecholamine levels are likely the cause of the post-exercise calorie burn. Ultimately, the mechanisms are less important than the fact that EPOC is the result of a metabolic perturbation that has to be repayed afterwards.

I'm not going to detail the next section of the paper as it dealt with a bunch of boring methodological issues. Sufficed to say that accurate measurement of EPOC requires that certain methodologies be adhered to. One huge confound, which is likely the cause of the 'exercise raises metabolism for 24 hours' thing is food consumption. It's easy to mistake the thermic effect of eating with an effect of exercise. Good studies take this into account. Othe issues such as taking into account baseline metabolic rate and subject characteristics are also important.

The next section of the paper deals with continuous exercise and the impact of both duration and intensity on EPOC. Without going into every paper detailed in the review, the picture that has developed from the research is that EPOC goes up linearly with increasing exercise duration but exponentially with increasing intensity. That is, higher intensity exercise generates the higher EPOC. This is true if the duration is the same or if the same number of calories are burned. That is, if two people both burned 300 calories during exercise but one exercised at a high intensity and one at low intensity, the high intensity guy would get about double the EPOC. The problem is that, even under these conditions, the EPOC is still pretty minimal. In one study, subjects who exercised for 80 minutes at 70% VO2 max (about 80% of maximum heart rate) had an EPOC lasting 7 hours. But it only amounted to about 80 calories extra burned. Not to mention that only the most well trained individuals could sustain such a workload in the first place.

Additionally, it appears that there is an intensity threshold to generate any EPOC at all, compared to exercise at 30-50% VO2 max (50% VO2 is about 65% of max HR or the typical 'fat burning' zone), exercise at 75% generates a larger EPOC. However, the total calorie burn is still relatively small overall, averaging perhaps 7% of the total energy burned. So if you burn 600 calories with high intensity continuous exercise, you might burn an additional 45 afterwards. While this certainly adds up over long periods of time, it's still relatively insignificant compared to the total energy expenditure of the exercise bout.


The next section of the paper dealt with suprmaximal work, intervals basically. Interestingly, the data available here finds that relatively short amounts of intervals can generate EPOCs comparable to much longer bouts of continuous exercise. Several studies measured EPOCs from relatively short interval workouts on par with studies using much longer (>50 minutes) of moderate intensity work. Still, the total magnitude of the EPOC was relatively small, equal to roughly 13% of the total energy used during the exercise bout. So while the relative amount of calories burned after interval training is larger, the total amount is still small. In one study, subjects ran 20X1 minute intervals above VO2 max with a 2' rest between. While the EPOC was about double that found in subjects who performed 30' at 70% Vo2 max, the total EPOC was only about 32 calories (135 kJ).

The next section of the paper dealt a little more with the issue of exercise duration as studies have identified an increase in EPOC with increasing durations. However, the effect is only significant for exercise performed at intensities greater than 50-60% VO2 max (60-72% max heart rate). However, unless folks are willing to do 60-90 minutes+ of training, this still doesn't amount to very much in absolute terms. This is especially true of lower intensity exercise where prolonged durations of 90' or more are necessary to generate a prolonged EPOC; even there the absolute magnitude of calories burned is still small.

Finally the paper examines the impact of resistance training on EPOC. A number of studies have been performed and found fairly prolonged durations of EPOC (15-38 hours) and an increase in metabolic rate of 9-11% over that time period. However, many of the studies used horribly unrealistic numbers of sets (60 sets of 8-12 in one study, 30 sets in another). Interestingly, a study of women found a much shorter duration of EPOC (60-90 minutes); the reasons for this are unknown. Perhaps the most interesting study was the one using a relatively low volume of training (4 exercises for 4 sets each) in experienced lifters; in that study metabolic rate was significantly elevated for nearly 48 hours after lifting. The paper points out that the average person is unlikely to be able to sustain either the volumes (30-60 sets) or intensities used in these studies.


The paper concludes that, despite the variability in studies, the intensity of exercise appears to be of the utmost importance in terms of generating an EPOC. However, most studies indicate that the total magnitude of the EPOC is unlikely to be very large. With interval type training, EPOC may approach 14% of the total energy expended but, generally speaking, interval training doesn't burn as many calories during the bout so while the relative amount may be larger, the total EPOC is still small. For submaximal work, an EPOC of 7% is roughly the average.

This doesn't really amount to much not to mention that, outside of trained individuals, most folks couldn't sustain the durations (90'+) or intensities (80% maximum heart rate for steady state work or supramaximal intervals) required to generate much of an EPOC. I would note that even beginners can work up to that level with a properly set up progressive program. One beef I tend to have with many exercise and fat loss studies is that the intensity or duration of the exercise is never increased as the folks become fitter. But that's a separate topic for another day.


The paper suggests that focusing on maximizing the calorie burn of the exercise bout itself and issues of compliance should be the primary goal. Because even if you burn a few extra calories after the exercise bout, if you increase how many calories you burn with exercise by a couple of hundred, that couple of hundred will have a much larger impact than the 15 extra you burn because of it.

But here's the thing, there seems to be a disconnect with the conclusion of this study and the results people are reporting with interval based types of fat loss programs.

Even looking at the original Tremblay interval study, where EPOC was unfortunately not measured, fat loss was significantly greater for the interval group despite a massively lower time investment and calorie expenditure. Something is going on.


It may be, and I suspect that it is, that EPOC is only part of the picture. Studies have found that interval training may increase enzymes involved in fat utilization more effectively (or at least more quickly than steady state exercise). A followup study by Tremblay found that to be the case and a very recent study found that only 2 weeks of interval training had a fairly significant impact on whole body and skeletal muscle capacity for fatty acid oxidation at rest.

This is assuredly mediated through both effects on gene expression as well as the glycogen depletion that occurs with high intensity activities; glycogen depletion itself enhances full body fat oxidation. Frankly, irrespective of EPOC and what happens during the exercise bout, if you increase the body's utilization of fat for the other 23 hours of the day you aren't exercising, that's a good thing from a fat loss perspective. Coupled with a calorie reduced/controlled diet, enhancing fatty acid oxidation during the day goes a long way towards explaining enhanced fat loss.

Another possibility, implied by the Tremblay study is that interval type training programs are generating some muscle growth. I say implied because the original study found less of a change in total bodyweight than the change in fat; that suggests that muscle was gained. Given the caloric cost of synthesizing muscle, that would give a 'sink' for incoming calories.

Of course, as the volume of training (number of intervals, number of exercises/supersets in interval based weight training programs goes up), so does the caloric expenditure of the bout itself. That's in addition to whatever small extra impact that you may get from the EPOC.

From Lyle McDonald's newsletter where he highlights his research review:

Research Review


Wolf A, Bray GA, Popkin BM. A short history of beverages and how our body treats them. Obes Rev. 2008 Mar;9(2):151-64.


Numerous studies have demonstrated that beverages containing sugar, high fructose corn syrup (HFCS) or alcohol are handled differently by the body than when sugar or HFCS are incorporated in solid foods and as a result the overall caloric intake from solid food does not adjust to account for the calories in these beverages. A consideration of our evolutionary history may help to explain our poor compensatory response to calories from fluids. This paper reviews the history of eight important beverages: milk, beer, wine, tea, coffee, distilled alcoholic beverages, juice and soft drinks. We arrive at two hypotheses. First, humans may lack a physiological basis for processing carbohydrate or alcoholic calories in beverage because only breast milk and water were available for the vast majority of our evolutionary history. Alternatives to those two beverages appeared in the human diet no more than 11 000 years ago, but Homo sapiens evolved between 100 000 and 200 000 years ago. Second, carbohydrate and alcohol-containing beverages may produce an incomplete satiation sequence which prevents us from becoming satiated on these beverages.


SEE CONT'D COMMENTARY BELOW

Lyle's comments: This is sort of a departure from the typical paper I talk about but I think it's very interesting and, as you'll see towards the end, does have some practical implication for dieters and folks looking to alter body composition.


After the necessary introduction, the paper first looks at changes in the patterns of beverage consumption within the US. They point out that by 2004, Americans were consuming over 135 gallons of fluids other than water or about 1.5 liter per day. Basically, Americans are drinking a lot but it isn't water; obviously it's something else.

The early part of the paper also trots out something called the Beverage Guidance Panel which, in my opinion, is about as useless as the current food pyramid. It's complicated and pointless, simply confusing people more about the issue. I'm not going to bother talking about it.

Quoting the paper, they state that "While consumption of healthful beverages is falling, consumption of the most unhealthy beverages is strong." While milk and coffee consumption are at roughly one half of their historical maximum, with tea basically unchanged, regular soft drinks are the most popular beverage; beverages sweetened with high-fructose corn syrup are consumed at a rate of over 35 gallons per year on average. The second most popular drink is beer which at least has some nutrients.

Positively, low-fat milk makes up two thirds of milk consumption with soft drink consumption trending downwards. However, this may be a false artifact due to how drinks are classified, energy drinks aren't being counted as soft drinks which is making it look like folks are drinking less soda. They aren't, they are just drinking energy drinks instead.

Looking globally, drink patterns have shown massive growth with soda products being consumed at a rate in excess of one billion drinks per day. Beer consumption has shown the greatest increase with tea showing a slight increase. Wine and milk consumption have fallen globally, presumably due to the introduction of all the drinks that have made America rich, proud and very fat (my comment, not theirs).

The next section of the paper got into what is arguably the most important issue of the paper: the simple fact that for all but the last 11,000 years, the predominant fluids consumed by humans were water and breast milk and nothing else. Now, they go out of their way to point out that milk is a complete beverage containing protein, carbohydrate, fat and water. Water is, of course water which provides no calories. This is important because numerous studies have shown that humans show poor compensation for fluid calories.

Let me explain that a bit. Compensation means that the body will adjust caloric intake at other times of the day (or days later) for a given caloric load. So say you eat a bunch of candy earlier in the day and it provides 450 calories. What you might see is that, later in the day, folks eat a few hundred calories less than they'd normally eat. The body 'compensates' for the food you ate earlier. The problem is that most liquid calories aren't compensated for well and figuring out why is of some interest to researchers.

The paper suggests that one of two possible mechanisms may be at stake here. First, we may simply lack a physiological mechanism by which to compensate for liquid calories. Second, it may be that liquids are treated essentially like water, being digested/absorbed too quickly to have any impact on food intake (normally eating food does things hormonally that tends to make you eat less later).

With that out of the way, the paper examines the majority of fluids consumed by humans from a historical perspective. I'm not going into deep detail for each or this would take pages. While interesting, this really isn't that relevant to the rest of the paper or how it impacts on things like weight, fat or body composition.

The main take home point of this paper has to do with how the body responds to different beverages. Various lines of research indicate that the intake of calorically sweetened beverages do NOT reduce the intake of solid food (the compensation issue I mentioned above). Reviewing the literature, they basically point out what I wrote above. Of some interest (especially to me since I like jelly beans) one study compared the intake of 450 kcal or jelly beans to 450 kcal of a soft drink. the jelly bean consumers actually reduced their food intake by slightly more than the 450 calories in the jelly beans (my next book: the Jelly bean diet) later in the day. The carb containing soft drink group not only failed to compensate for the drink but also increased their intake of other foods slightly. That is, not only did they get the added calories from the soft-drink, they ate more food as well; a double whammy in terms of weight gain.

Continuing on, the paper addresses the issue of why the body shows weaker compensation to some fluids; the exact reason is unknown. The propose that one mechanism is in the way that the GI tract responds to the form of the food; solutions can stimulate stronger sensory responses than solid food (e.g. sweet drinks taste sweeter than sweet foods sometimes). As well, the components which make up the beverage or food may play a role.

Obviously the sight and smell of beverages are important, we may react badly to a repugnant or bitter smelling drink and well to a good smelling drink. How drinks affect the taste buds comes next; humans can taste sweet, sour, bitter, salty and something called umami. There is also a taste bud for fatty acids.

A sickness response to a drink can cause an aversion to foods down the road. Remember when you drank something and you threw up afterwards, and how the smell of that drink would make you gag? That's what I'm talking about. The sight and smell of foods also affects hormonal response, there is something called the cephalic insulin response for example, insulin can go up when people smell or taste sweet foods, long before it hits the bloodstream.

Then comes digestion where mixing with the other components of the stomach affects many things, including digestion rate. Average digestion rate of fluids is 1 cal/minute with water digesting the most quickly (no calories). Other drinks digest at relatively slower speeds depending on the composition with fat containing beverages emptying slowest.

Moving into the intestine, more stuff happens including the release of a number of different hormones many of which are involved in appetite. I don't want to detail this as there are 15 or more that may play a role here. The pattern of release of these chemicals depends on the composition of the drink and this is where we can start to see the problem.

Carbohydrates alone stimulate the least number of appetite blunting factors, protein and fat stimulate the release of more. So you'd expect much less of a compensatory response to a drink containing protein and fat (think lowfat milk) as compared to one containing only carbohydrate (think fruit juice or a high sugar soda). Which is exactly what the studies have shown. Milk shows a nice normal compensation to intake, it might as well be liquid 'food'. Soft drinks show no compensation.

So folks living on sugary drinks are causing themselves major problems. Not only do the drinks themselves have scads of calories, the body doesn't compensate for their intake. So all of those calories essentially end up being 'added' to the normal food intake (which is just as often awful in folks who drink lots of soda).

Alcohol is weird as it's treated strangely in the body. I've mentioned in previous newsletters that alcohol intake shows a weird relationship with bodyweight. Weight often goes up with alcohol intake in men but either stays the same or goes down in women. What few direct studies exist suggest that alcohol intake does not cause compensation of food intake later on. So what explains the gender difference? Most likely, men drink in addition to eating (beer and wings) while women drink instead of eating (glass of wine for dinner). Oddly, at least one piece of research suggests that regular drinkers may be more active. It may also be that drinkers under-report their true food intake.

The paper than concludes although they don't say much I didn't mention above. Humans didn't evolve on anything but water and mother's milk with other drinks such as alcohol and soft drinks coming into common usage at a much later date. Because of this, we don't appear to have evolved good mechanisms for dealing with fluid calories.

Liquids tend to digest quickly (although fluids with protein and fat, such as milk, are much slower) and carbohydrate only drinks such as soda don't release as many of the appetite blunting peptides during digestion as whole food (or milk which is a liquid whole food). This makes the consumption of sugary drinks (fruit juice or soda) a major problem. People don't compensate for intake and end up simply adding the massive amount of calories to their diet, which is often bad to begin with.

As a final take-home comment, I'm reminded of a client I had years ago. He wanted to lose weight and one of the habits I identified in him early was the intake of multiple cans of full-sugar soda. Simply switching him to diet soda saved him something like 800-1000 calories/day, he started losing at a nice 1-2 pounds per week with no other change to his diet.

In summary, in terms of the impact of fluid calories on bodyweight, bodyfat and body composition,

1. Milk good: plenty of studies show improvements in body composition with regular dairy intake
2. Non-diet soft drinks and fruit juice bad: lots of calories, no fullness, no compensation
3. Alcohol: it's complicated....we need more research.

So in the meantime it's OK to drink guinness right

I'll help do research

Keeps me full

Hey, there's no definitive answers wrt to alcohol so have at it.

That's my theory that I live by at least.

I'm drinking right now, lol

well as I thinkit was Groucho that said - OK i won't drink any more....

but...

Iwon't drink any less either...

hey you could be the poster boy for alcoholism - 5 drinks a day and look like steve

Hahahaha.....

Steve the drunk.

That would be good for business.

Matt has an excellent website found at AMP Training Systems - Home. Kind of the hard-head of the fitness industry, he has a writing style that is gritty and clear to the point. My kind of guy, actually.

********************

What does the word “functional” mean to you?

If you've had any sampling of the modern fitness industry, “functional” will probably mean doing exercises that have a high carryover to the motions and actions found in most team sports.

It could just as easily mean standing on a wobble board doing one-handed dumbbell presses, in order to improve “core stability”.

Have you ever stopped to think what “functional” really means, though?

The word itself should give you a hint. A more appropriate definition of functionality would be “the way the body's systems work in order to create motor output”, to paraphrase the late Mel Siff.

In other words, functional training is a formal way of saying “training to improve how the body works in order to perform in specific ways”.

When somebody says that something is “functional”, the response should be “functional for what?”. Functional training is not just a discrete thing you can point to. It's not a style of training, as much as people like to quantify training in this way.

Rather, what seems to be happening is that people are conflating the concepts of sport-specific and instability training with functionality. Both of those approaches certainly have utility, but they are only “functional” for a limited set of activities.

The actual degree of functionality for any given exercise is highly dependent on many aspects of the sport motions in question. Too often people take the idea of specificity to the extreme; but specificity to a movement or action does not require simulation of that action.

Different exercises will have different degrees of carryover. What matters is not necessarily trying to simulate all aspects of the sport, but rather to pick and choose the exercises and methods that can best develop any of several abilities.

As an example, squats and leg presses could be considered relatively nonfunctional for a distance runner. Yet, we know that these exercises have a clear benefit. Why?

They prepare the legs for the absorption of forces. They help to develop and maintain muscle mass. They assist in force production. The list goes on; even though a squatting motion isn't involved in running, squatting still has a degree of functionality for distance running.

Some would even argue the point of the squat being “more” functional than the leg press; but really, considering that both exercises are general development to the runner, how can this be the case?

Functionality is entirely contextual. An exercise or training method can be functional for one activity, and nonfunctional for another.

Bodybuilders and those of you only interested in looking better, you can get away with just about anything. For the purposes of muscle hypertrophy, resistance is resistance, and tension is tension.

The difference is between general and specific training methods. Ideally a training program will be some blend of general training, which develops the overall “fitness” of the athlete, and specific training, which directly improves the sport performance.

Just how this comes to pass is up to the strength coach and the programming s/he chooses to use; but that's a whole separate article.

Exercises don't have to be sport-specific in order to have value to anyone. Further, if you're a recreational lifter or a gym rat only interested in improved health and fitness, your choice of exercises aren't that critical.

Yes, you most certainly do need to take care of basic movement abilities, such as squatting, pressing, pulling, twisting/rotating, lunging, and so on. However, it's a strawman argument to say that simply using these allegedly “nonfunctional” exercises will somehow interfere in that, or that the two can't be used together in a program.

Functionality is entirely context-dependent.

Extremely true...

Mal, I'm glad someone reads these things!

375 views - someone's reading - not everything requires a comment - though i tend to like having the last word - so I comment more than i should (explains my post count

Well it's nice to hear thoughts. I post them not only to share some of the stuff that 'comes across my desk.' I like discussion too.

Here's an excellent article from Mike Boyle:

michaelboyle.biz - The Best Source of Performance Enhancement Information on the Internet - Hamstring Dominance - Brijesh Patel

I was just reminded of this on another forum:
Lurn 2 squat good -- E-ZY!

Here is a Q&A from Lyle McDonald's newsletter. If you don't read his newsletter, I highly recommend it. It's the best out there I've seen:

I have a question for you that I've never seen you address. If you get a chance to post about this somewhere, I'd love to see it:

How to find a reliable trainer...

Every time I read something by you explaining how to lift a weight (e.g. the great bench press posts) and how most people do it wrong...it just scares me to use any old trainer at the gym. We can't all hire you (and w/ your speed skating I guess no one can right now...) But I would think that some trainers have better certification than others...so a little guide for relative newbies like me would be much appreciated....