In Training the Obese Beginner: Part 1 I took an apparently somewhat complex look at some of the physiological “defects” that are often seen with the development of obesity. This included a look at insulin resistance/the Metabolic Syndrome, resting and exercise fuel use, and the issue of impaired mitochondrial function.
I also finished with a sort of grab-bag of practical issues related to obese beginners including a general low tolerance for activity along with a couple of psychological issues and others. Hell, just go read Part 1 again (or for the first time), it’ll be faster than this awful summary.
Continuing from that point, today I want to look at a few more physiological issues including increased muscle mass in the obese, a brief look at metabolic rate (mainly a myth-buster thing) and then finally at some of the realities of exercise in this population.
Increased Muscle Mass
One of the consequences of becoming obese, surprisingly enough, is that a portion of the total weight gained is lean body mass (LBM). On average, of the total weight gained, LBM may make up about 25% of the total. So if someone puts on 100 pounds of weight, and this is without training mind you, as much as 25 pounds of it could be expected to be LBM. I’d note that this process is not unlimited, even the very obese seem to hit an upper limit of LBM (which is very similar to that seen in natural lifters); above that point further weight gain is almost pure fat.
In any case, I’d also mention a portion of this LBM is actual skeletal muscle. Ever notice the leg and calf size on bigger folks? They are typically huge with the strength levels to match. Think of becoming obese in the long-term as the ultimate in progressive overload, the increasing body weight acts as an overload for lower body muscles and they hypertrophy in response.
But not all of it is actual muscle tissue, some of it is what researchers are now calling inessential LBM. Basically it’s increased connective tissue, glycogen, water, etc. that is gained as body weight increases. It’s also usually accepted among obesity researchers that, because of this gain in LBM that accompanies becoming obese, up to 25% of the total weight lost can come from LBM without any detriment (and yes this does go against the general belief that ANY LBM loss on a diet is a negative).
That is, unlike in the situation with leaner individuals, where LBM loss is a problem that needs to be dealt with/stopped in its tracks (since the majority of the LBM being lost is skeletal muscle), loss of LBM in the extremely obese is less of an issue. Quite in fact, to achieve a “normal” body weight (whatever exactly that means), loss of some of the “extra” LBM may be necessary.
Basically, what’s being lost on the way down is what was gained in becoming obese in the first place so it doesn’t matter in the big scheme. Not all agree, of course, some differentiate losses of inessential LBM (glycogen, water, minerals, connective tissue) and essential LBM (muscle mass, etc.). The first can be lost without concern, the second maybe not so much.
So why am I bringing this up other than to show off my incredible knowledge of useless physiological minutiae? Here’s why: In training the obese beginner, individuals with a proximity bias for the weight room often put a lot of their energy into having the obese lift weights. They figure that’s what should be done in the gym, and that’s what they like to do, so that’s what all their clients do. And it tends to be a real waste of time and energy beyond a certain point.
Some of this also comes from the still gross misconception that “muscle burns a ton of calories” (a myth I took apart in Dissecting the Energy Needs of the Body – Research Review) and the idea that increasing muscle mass in the obese will help “burn off the fat”. That is, they hope to jack up metabolic rate by increasing muscle mass.
Which is a futile activity because the effect is minimal (on top of the fact that the obese are already carrying extra muscle mass). A pound of muscle burns about 6 calories at rest, you have to add a ton to impact on metabolic rate (see also the next issue I discuss, low metabolic rate isn’t a problem). And that takes a lot of time, time better spent focusing on active fat loss.
This segues into the misguided notion that increasing muscle mass will automatically lower body fat percentage, which I took apart in Reducing Body Fat Percentage by Gaining Muscle – Q&A. Losing fat always has a much larger impact in this regard as the math clearly shows. Gaining five pounds of muscle has a negligible impact on body fat percentage (and health parameters in the obese) compared to losing five-pounds of fat; and the second can be accomplished in a fraction of the time (weeks for the fat loss versus months for the muscle gain). Under some extreme conditions, a very obese person can lose five pounds of fat in a single week; the same muscle gain takes much, much longer.
I’d also note that, in terms of time spent exercising, you can pretty much always burn more calories during cardiovascular activity than in the weight room, not that you can burn a lot with either under most conditions (see the final topic today). And before you bring up EPOC/the afterburn effect in the comments, go read Effects of Exercise Intensity and Duration on the Post Exercise Oxygen Consumption – Research Review. The impact is minuscule approaching irrelevant: the calories burned during activity are the major contributor no matter what you do.
Which isn’t to say that weight training isn’t important or useful for other reasons (which I’ll cover in part 3) when training the obese beginner; that’s not what I’m saying here. Rather my point is that spending an inordinate amount of time on weight training with the obese beginner is simply a misdirected effort. It’s time spent that is unlikely to massively impact on the outcome but will take time away from other, relatively more important activities. Should you do some? Yes, absolutely. Should you do tons? Generally not.
I’d note that even in the Biggest Loser Feedback piece I ran, the writer mentioned that their training was about 25% weights/75% cardio. I could even see a more skewed ratio but the Biggest Loser is mostly about doing what looks good on TV, not what is the right kind of training. And watching people do cardio isn’t very exciting so they have to dick around with weight training stuff to get an hour’s worth of television out of it.
While this doesn’t really have a huge practical impact, I want to mention it today since I brought up metabolic rate above. There is a long-held belief that the obese suffer from a low metabolic rate, this idea has been maintained for decades now. Now, I would mention, and readers who want more detail should read Metabolic Rate Overview, that there are four different components to metabolic rate and the one I’m talking mainly about right now is resting metabolic rate (RMR).
But this idea, that the obese have a massively low (for their weight) RMR, long-held, is simply wrong. Outside of weird pathologies (e.g. the handful of leptin deficient folks), the simple fact is that studies find what you’d logically expect: larger bodies burn more calories at rest (as well as during activity). That is, the obese have higher resting metabolic rates than their skinnier counterparts. In fact, a recent paper mentioned that the never-ending search for proof of a lowered metabolic rate in the obese led obesity researchers down the wrong path for years; they were looking for a non-existent phenomenon.
I would note that one risk factor for becoming obese in the first place is a lower than predicted metabolic rate. That is, some people, BEFORE they become obese, have a lowered metabolic rate relative to what you’d expect based on their weight; this tends to be due to lowered sympathetic nervous system output (at one point it was stated that most forms of obesity known were related to low sympathetic nervous system output) although thyroid dynamics can also a play a role.
And this lowered metabolic rate tends to predispose them towards weight gain under certain conditions (such as the modern environment with its overabundance of calorically dense foods and low requirement on activity). But this is one of those issues where it’s the initial low metabolic rate that is contributing to the development of obesity in the first place. It’s a cause, not an effect.
The point is that by the time someone has become obese, this initial “defect” has reversed itself; larger individuals have higher metabolic rates than smaller (though there is still some variability at any given body weight). You simply do NOT see obese individuals with exceedingly low RMRs. Again, not unless there is some massive metabolic problem (such as leptin deficiency) and that can’t be attacked with diet and training anyhow. The simple fact is that, when measured, obese individuals always have higher RMR’s than lighter individuals.
Now, I’d mention again that I’m only talking about RMR above which is reliably increased in the obese individual; but RMR only makes up about 65-75% of total daily energy expenditure. The others play a role. However, some of the other components of total energy expenditure, such as TEF (thermic effect of food) or the thermic effect of activity are often decreased.
TEF can be cut in half due to insulin resistance for example. On a 3000 cal/day diet, for example, where you’d predict TEF to be 300 calories (10%), it might be cut to 150 cal in someone with insulin resistance; which I noted in Part 1 is common in obesity. While this isn’t a massive effect, it will add up over time and can’t be discounted.
As well, daily activity is often decreased in obesity. Larger individuals simply tend not to move around as much as their leaner/lighter counterparts (an old experiment is to go to the mall and see who rides the escalator and who takes the stairs for an example of this). So even if RMR may be higher due to the larger body, and even if the energy burned during activity is higher, total energy expenditure may still be lower than expected (note that I didn’t say it was “low” but lower than expected or predicted) due to a decreased TEF and reduced overall daily activity.
Again, none of the above is really relevant to the practicalities of the obese beginner, at this point I am just showing off my knowledge of physiological minutiae. I’m also an obsessive compulsive completist with a need to destroy long-standing and utterly silly myths and this is one of them; the idea of the low metabolic rate in obesity which simply doesn’t exist outside of a handful of severe medical pathologies. Moving on.
The Realities of Exercise for the Obese: A Primer
In Training the Obese Beginner: Part 1 I mentioned that generally low exercise tolerance is common among the obese. Note that common doesn’t mean universal and invariably someone in the comments will trot themselves out as an exception. Once again, the Biggest Loser show notwithstanding, expecting a beginning obese client to do a ton of activity out of the gate is usually a mistake. And one that often backfires. Sure, you can make them do it but just because you can doesn’t mean you should. The Biggest Loser gets away with it by putting folks on TV and holding out a $250,000 carrot and fame as the reward. This doesn’t apply to most people.
And one of the realities (and in fact ironies) of exercise is that usually the only people who can burn a ton of calories with exercise are folks who are already well-trained (and usually don’t need the calorie burn). That is, trained athletes can burn a massive number of calories in exercise fairly readily.
Even an hour of moderate activity may burn 600 calories, and a trained athlete can do that for hours at a time. An hour of hard activity may put them nearer 900-1000 calories though it can’t be sustained for quite as long a time. But they are usually already lean and don’t need it (though when athletes do need to drop fat it’s usually pretty easy because they can burn such a ludicrous amount of calories with even moderate intensity activity).
This is actually a topic that I intend to cover in greater detail in a later article series but the realities of exercise are that most will not and can not burn a ton of calories during activity of any sort. Under most conditions, 5 cal/min is pretty common for a beginner (that’s 300 calories per hour) and values of 10 cal/min are sometimes achievable. Expecting much more than that is not realistic.
Please note that I’m not saying that these are absolute cutoffs or that no-one can surpass them. Just that they are fairly standard “average” calorie burns for activity by untrained folks. Someone will always hold up their “friend who was able to run a 6 minute mile at 250 pounds and burn more calories than this” as an exception but that’s all it is; an exception.
I’d note that bigger individuals burn more calories during activity simply by dint of being larger. But their ability to do a lot of activity is usually quite limited as I’ve been prattling on about. Getting ahead of myself, I’ve seen people for whom, quite literally, 5 minutes continuous walking briskly on the treadmill had them fatigued. That doesn’t provide much potential for calorie burn.
As I’ve written in several books, the contradiction is that the people who need to be able to burn a lot of calories in exercise (to skew energy balance) towards fat/weight loss usually can’t; their tolerance for exercise (either physically or psychologically) is simply too low. And the folks who can burn a ton of calories in activity usually don’t need to.
It’s a real catch-22. And I’m Yossarian.
In fact, many of the exercise studies done to date simply don’t support a massive impact of exercise on weight/fat loss, at least not in terms of the quantity lost (exercise certainly impacts on the quality of what’s lost; that is LBM vs. fat mass). And certainly a few have found an impact but tended to use fairly large amounts of activity (one that comes to mind threw people into 2 hours of moderate activity 6 days/week and generated pretty significant fat losses).
And spare me the interval studies; even the famous Tremblay interval study only saw a fat loss of a few pounds over 12 weeks. That’s insignificant on top of the fact that most beginners won’t have the exercise tolerance to do the intervals (a point that every researcher involved actually makes within the full paper; but most only read the abstracts).
Now, this actually does have one huge practical implication that I’ll discuss in more detail in a later part of this series and that is this: altering the diet has a much greater chance of drastically impacting on energy balance than activity in this population, especially in the beginning. Because while increasing activity by 500 calories/day (assume 50-100 minutes of moderate-low intensity activity) is usually unrealistic, that same deficit can generally be created through diet much more easily.
And I’m not even talking about “going on a specific diet” in this case; often simple qualitative changes to the diet can be made. As an example, I had a client years ago who was drinking 4 or more full sodas per day. I suggested he switch to diet soda (or water). That change alone cut his calories intake by an easy 500+ calories day. Result 1 pound+ fat loss per week with no real changes to his diet. But I’m getting off track.
Back to exercise and its general irrelevancy in terms of significantly impacting energy balance. Realistically, on average, exercise simply can’t and won’t have a massive effect. Please note, there are other potential benefits to activity such as increased adherence, health benefits, etc.; burning calories is only one possible end-goal here.
But the bottom line is that, short of doing massive amounts of it, exercise is unlikely to have a massive impact on body weight or body composition. And most untrained individuals (whether obese or not) are not capable of massive amounts of exercise.
This was actually apparently really big news several years ago (in Time magazine I think), the realization that moderate amounts of activity (say 30-40 minutes a few times per week) wouldn’t make you lose tons of weight. Wait, this is news? Hell, I wrote about this in The Ketogenic Diet nearly 15 years ago.
I guess the news is more in how exercise was either misrepresented (as a cure-all for everything) or misinterpreted (as a cure-all for everything). The expectations were simply unrealistic; trainers and exercise biased folks either sent the wrong message or the general public heard the wrong thing (it’s usually a subtle combination of the two). And the bottom line is that most research does not find a major impact of realistic amounts of exercise on the quantity of weight loss.
However, most of those studies used not only fairly moderate amounts of activity, they also didn’t do anything in terms of progression. They simply gave the same moderate amount of activity throughout the length of the study without ever increasing anything.
Which brings me to a qualification of a statement I made above, that the beginning obese trainee usually doesn’t have much tolerance for activity (again, either in psychological or physiological terms). And that qualification is to add the statement “at least not initially” to the sentence. But it can be improved over time.
In fact it always does improve and usually fairly quickly. That’s one advantage of being untrained in anything, you see faster progress in most things, at least if the training is set up correctly. That rapid improvement has its own set of benefits in terms of adherence as well (something I’ll come back to later in this series) But the point is that, to some degree, the training should and must progress either in terms of volume (duration), frequency (times per week) or intensity (difficulty). Or all three. Again, this is a practical issue that I’ll get to later.
In a final related vein, I’d point out, and this will sound like a gross overgeneralization (which it is) but most overweight individuals don’t particularly enjoy exercise in my experience. It’s probably safer to say that most people don’t enjoy exercise, mind you; but this is a series about training the overweight beginner. The reasons for this are assuredly multi-factorial and ultimately irrelevant (again, someone will always trot out an exception, usually an ex-athlete who became obese later in life and still loves training when they get back to it but that’s not the general population we’re talking about here).
Whether it was bad experiences as a kid (how many my age remember the horror of the President’s Physical Fitness test and the emotional scars it left) or simply the fact that exercise is not enjoyable when you’re bigger (for reasons ranging from physical discomfort, to the realities of larger individuals moving vigorously, to the stress of being in a gym surrounded by buff elitist assholes). This is yet another barrier to getting into a regular training program, on top of everything else I’ve discussed. The typical obese individual typically don’t want to do it in the first place and, when they do, it doesn’t have a big effect on anything. Hardly a strong selling point for exercise.
And this fact (or at least gross overgeneralization) has a huge practical implication for training (relating to several psychological issues including affect, positive reinforcement and others) that I’m going to make you wait until later in the series to read about in detail. You can probably guess what they are (and what I’m going to suggest to address it) but you’ll have to wait in any case.
- Lean Body Mass Maintenance and Metabolic Rate Slowdown – Q&A
- Training the Obese Beginner: Part 3
- Exercise and Weight and Fat Loss: Part 1
- Steady State vs. Intervals: Explaining the Disconnect Part 1
- Training the Obese Beginner: Part 5