Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults

Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults.

This study popped up on the social media yesterday and it’s caused quite an uproar among the pro-lifting crowd, mainly thanks to the last lines of the abstract which seem to say that “cardio is better than lifting weights”.

I don’t want to get into a full dissection of this paper, because I think, like most media-driven study-hysteria, it’s importance is overblown. I’d like instead to go over some thoughts that occurred to me as I read through the findings which might help slot these findings into a pragmatic framework.

  • I’ve had prior experience, both directly and in advising others dealing with “stuck” clients, with overweight and obese people not responding to the prescription of “just lift and watch your diet”. You can conjure up your own Pubmed explanations for why this might be, but the reality of it is that some folks just don’t respond well to that plan, and I don’t believe it’s because they are “really” just eating too much.
  • What has, however, worked consistently is taking these people away from an exclusive emphasis on lifting (and intense interval cardio) and getting them to do add light to moderate aerobic cardio. Even a half-hour to an hour of aerobic cardio, something as simple as a walk (my rule is “do something that makes you breathe hard”), can make all the difference, and suddenly the fat starts to come off.
  • Despite the internet trope to the contrary, I have known even “normal weight” (meaning normal body comp) people who see no substantial visual changes from lifting weights alone. Yes, they develop more muscle and drop body fat (by percentage), but the way those changes distribute just creates a “does this guy even lift?” effect. Underweight people (“ectomorphs”) of either gender will naturally tend to “shape up” via lifting, as will pudgy people who might otherwise be naturally lean outside an environment encouraging overeating. People who seem to have a genuine biological tendency to be heavier and “thicker” (“endomorphs”) don’t always seem to get this benefit, and they really seem to need aerobic cardio along with diet and lifting to see the best effect.
  • Most of these people have been women out of their early twenties. Whether this applies across the board or is an artifact of my own construction I leave to the reader, but I do believe there may be some genuine metabolic reasons behind this. It wouldn’t surprise me to find that this can apply to people of any age or gender, though, as my experience need not be representative of the statistical reality. The point is having the strategy when you run into the roadblock.

What this paper found doesn’t conflict with these observations.

The two modes of exercise consistently differed in their effects on body composition. Body weight and fat mass significantly decreased in both AT and AT/RT but not in RT, suggesting that aerobic exercise is more effective in changing these measures. However, the change in lean body mass in both RT and AT/RT was significantly greater than that in AT, a finding supported by similar observations for the measure of thigh muscle area. Having the benefit of both modes of exercise allowed AT/RT to decrease body fat percent significantly more than either AT or RT, due to decreased fat mass combined with increased lean body mass. Similarly, there was an apparent additive effect of the two modes of exercise on waist circumference, as AT/RT significantly decreased waist circumference more than AT or RT.

I have some questions about their methods for assessing calorie intake, but for the moment let’s just assume that their report of intake as being more or less equivalent between the three groups is right.

You could then say “Well with a tighter diet these folks would lean out by just lifting weights.” Let’s grant that this is true, although it need not be. Even so, there are people, and I include myself among them, who’d rather have the food and spend the time training harder. This need not even be a physiological effect, but rather an effect of “living what you want to be”, so to speak, and that’s a factor I’ve come to believe is far more important than any reductive measure of ‘efficiency’.

As I’m reading this, that strategy is validated: “there was an apparent additive effect of the two modes of exercise on waist circumference, as AT/RT significantly decreased waist circumference more than AT or RT.”

That may not seem like much, but I think that this sentence, when taken with the finding of increased LBM and reduced fat mass, is the real clincher. Even though, strictly speaking, there may be no superiority to the combined modes of exercise in terms of absolute fat loss or weight loss, that’s beside the point.

The authors reach that conclusion based on ‘time-efficiency’ and an assumption that it is the absolute reduction in fat mass that is definitive of health. While I can admit (grudgingly) that the former will be a factor of importance to some people, I can’t entirely accept the latter. Amounts of fat mass are certainly important, but if we’re going to talk of health then we can’t really leave out the importance of LBM, the distribution of fat mass relative to LBM (which, as measured by waist circumference, we saw improved in an ‘additive effect’ by the combined modes of training), and the myriad positive effects of placing the body under regular loading.

I don’t entirely agree with the author’s conclusions, but the study itself is interesting and I believe that, if anything, it suggests that those looking to reduce fat mass and improve the distribution of lean and fat mass should be lifting and keeping some conditioning work in the mix.

Weight Training for Fat Loss

If you’re not aware, I’ve been dieting since July. Why, you ask?

Because I got fat over several years of bulking and generally not caring what I ate. Now, to look at me, you wouldn’t necessarily think that. By “regular people” standards, I’m fine. It’s by fitness or bodybuilding standards that I’m fat. So I decided to do something about it.

Training for fat loss has become a hobby-horse of mine, because I think most people just do it inefficiently. For most folks, “fat loss” means “go run 10 miles a day while eating lettuce”. I’d like to think that’s been pretty much discredited in fitness circles, though the method of overemphasizing aerobic training and eating a starvation diet hasn’t totally vanished.

The would-be experts in the fitness community have kept up, to a point, although we can’t ever underestimate the power of humans to make something stupid. Even the “science-minded, evidence based” [sic] crowd tends to be a little dogmatic and uncritical with their suggestions.

This is why you have the people that want to aggressively strength-train and do a metric ton of HIIT, because low-intensity/steady-state (LISS) cardio makes you fat. Or the groups that want to rely almost exclusively on the “functional training” [sic] paradigm, with all the metabolic circuits and conditioning and whatever.

Nobody really seems to look at it from a rationalist standpoint. Big shock in this field, right?

The first step here, as with any problem-solving scenario, is figuring out exactly what we’re trying to accomplish. This sounds like a no-brainer, but you might be surprised.

Obviously our major priority is the eponymous “fat loss”. To delve into it a little further, we’re trying to get the fat out of the fat cells (lipolysis) and then burn it up so it isn’t re-stored (oxidation).

The biggest influence on this process is going to be your diet. We can go on about the diet all day long, and there’s a million and one ways to put it together. Let it suffice to say that you’ve got to create a net energy deficit, using up more energy per day than you take in. If you’re doing that and providing adequate essential nutrients (which is an extremely important caveat, all you “insulin magic!!” readers), then you’re going to be creating the catabolic state required to mobilize and metabolize fat.

Sounds good. However, we’ve got a decision to make. This system-wide catabolism, unchecked, is also going to start eating into our precious LBM (muscle), too. This is an unfortunate consequence, but it’s really unavoidable; your body is going to cannibalize nutrients from both muscle and fat, in a ratio that is (largely) determined by genetics. While we can’t do that much about it, we can take some steps to mitigate muscle loss as much as possible. If we don’t want to start shrinking, then we have to take some kind of steps to preserve muscle mass.

The third factor – and this is going to be the most crucial of all, in my opinion – is system-wide recovery. Not only is this the most crucial, it’s also (conveniently) the one most often ignored.

Recovery is a function of two things:  how much stress is imposed on your body, and how efficiently your body recovers from that stress.

The former is a result of your workouts and your lifestyle; the latter is influenced by lifestyle, but is mainly determined by established biological processes. It’s fair to say that you’ll always have more control over the amount of stress you create than you’ll have over your recovery ability. Recovery ability is limited; stress is not.

The analogy I’ve used in the past is a sink full of water. The water is your recovery ability; the faucet adds water to the sink, increasing your recovery, while the drain represents stress, taking water away.

It’s important to note that everything in your life can be a stress to some degree or another. We often recognize that exercise is a powerful stress, but gloss over the fact that a hard day at work, going through a messy divorce, or even being sick are also draining that water.

Your diet modulates recovery ability, but only to a point. You can think of calorie restriction as cutting off that faucet. If you don’t limit the amount of water draining out, then sooner or later the sink’s gonna go dry. On the other side of the equation, even turning on the faucet full-blast isn’t going to keep the sink full if you knock a hole in the side of it – some folks may think you can out-eat a massive training load, but that’s not always the case.

Now think about what happens if you cut off the faucet (low-calorie diet) AND knock a hole in the sink (lots and lots of training). You’re gonna run out of water pretty damn fast. So why is it that most people trying to diet do exactly that?

Training on a diet needs to be a fraction of what you’d do at your best. Note that this is a relative condition. If you’re very conditioned and very acclimated to high-volume weight training, then you’re going to be able to handle much more on a diet, compared to a person that does little cardio and trains HIT style. Dieting is always a reduction compared to your relative ability.

The result is that we have to carefully manage the amount and the difficulty of any exercise we do according to how much food we’re taking in. Obviously if the goal is to maximize fat loss, we’re going to have to make some concessions if we don’t want to end up a crippled, burned-out mess.

This gives us a quick and dirty list to check our priorities:

1. Increase lipolysis and fat oxidation
2. Maintain muscle mass
3. Do 1 & 2 without overworking ourselves.

Any decision we make as far as what to do in the gym should always stick to that list of priorities. If an action or behavior doesn’t fit, or it conflicts with one of the goals, then you’ll have to ask yourself why you’re doing it.

Training Intensity – How Heavy?

I’ve stated before that I see training stress as a sliding continuum of effects. Training hard, with very heavy weights and a fairly high workload, is necessary to trigger muscle gains. But the goal on a diet isn’t to build muscle; all we need is to hang on to it. And hanging on to muscle is easy, requiring only a small fraction of the total stimulus it takes to build.

This is why we need heavy training on a diet – it stimulates the muscles to hang on to protein, giving us that muscle-sparing effect we need.

Intensity is always the prime variable, the one thing we don’t have to futz with too much, so you’ll always want to keep something at least moderately heavy in your training. The problem is people seem to not understand what “heavy” means, so defining it is probably a good idea.

When I tell you to lift something heavy, I’m talking as a percentage of your 1RM. Heavy in this context is anything at or over 70% and right on up to 100% (give or take, since you’ll never be completely accurate). You always need to be training with weights in this range if you have a goal that involves being strong or being pretty.

Now, people read that and think “gee, he said I should be training heavy” and then they’ll go out and struggle with maximum weights each session, grinding themselves into paste trying to knock out set after set of heavy triples.

That’s not what I mean.

This is where I bring in the RPE scale. The Rating of Perceived Effort is a way to grade the relative difficulty of your sets. For dieting purposes, I think most of your time should be spent at 7-8, with an occasional 9, on a scale of 1-10.

To give a little more detail, I’ll refer to Mike Tuchscherer’s excellent RPE chart. I’ve used informal methods of grading effort for years, but I really like how Mike quantified it so I’ve been using his system for the last year or so. A 10 is your maximum effort; no further reps are possible. A 9 is still very hard, but you’ve got at least one more rep left in the tank. An 8 will be difficult, but there will easily be 2-4 reps left in you. A 7 will be “speed” work, meaning that the bar moves quickly if you apply maximum effort to it.

This means that a set of 10 and a set of 3 can both be “maximum” if you reach a 10 RPE – the point where you could not do another rep without assistance. These maximum “straining” or “grinding” reps are very taxing on your system, regardless of weight on the bar and regardless of the rep range.

I think people make the mistake of equating “train with heavy weights” and “train with an RPE of 10”. On a diet, I think this is probably the biggest mistake you can make. Regardless of the weight used, you should be working with weights and sets that aren’t absolute grinders. A weight can and should be heavy enough to present a challenge, but not so heavy that you can’t complete the rep without blowing a blood vessel in your eye.

To summarize, “training heavy” is different from training with high effort. Intensity is just the percentage of your maximum; it’s a high weight, not a high degree of effort.

Training Frequency and Volume – How Much and How Often?

Most people just do too much work on a diet. I don’t know how else to say it. Dieting is not the time to try and improve fitness; it’s the time to maintain what you’ve got.

Since we know that recovery ability is impaired and your ability to build new muscle is heavily impaired (to the point of nonexistence), there’s little rationale for doing high volume strength workouts while you’re dieting.

Volume is the first thing that should be scaled back. This means that you need to be doing less across the board; maximize your training economy. Do less sets, do less exercises. Focus on the lifts that will net you the greatest effect with the least amount of work.

As far as frequency goes, it’s often stated that hitting a muscle group three times per week provides the best stimulus, and I think this holds true even on a diet. If you’re training with an economical and minimalist routine, three days per week, along with some conditioning work, then you’re going to be doing just fine on most diets.

That said, I don’t think that even the number of workouts is sacred. It would be the last thing I’d cut back, but experience has shown me that some people just aren’t going to thrive on even three bona-fide strength workouts each week. If you can’t recover on three sessions, then cut back to two. I don’t necessarily think that two sessions is ideal, but we have to consider priorities: fat loss has to come first. If your diet isn’t sufficient to recover from three sessions, then cut it back.

I can’t see many instances where doing only one session per week would be a good idea; if you can’t recover from two weekly sessions then your diet is just screwed up, or you’re blowing your wad on your current workouts.

Now I know some of you are reading this and going “but I train 4/5/6/7 days per week and I lost 10 20 50 lbs!!!”. I’m not going to dispute that very high frequency training is effective, but here’s why I don’t often suggest it: most people can’t even get it into their heads that they don’t have to blast themselves to pieces in order to have a good workout.

Unfortunately that thought process is utterly incompatible with high-frequency lifting. If you’re going to weight-train more than four days per week, you have to drill it into your head that these will not be your typical workouts. You’ll only be doing 1-3 exercises, for lots of sets, generally low reps, and you won’t be getting anywhere near failure (on the RPE chart, these sessions would be 7-8, maybe one harder 9 each week).

I will say that if you can do such a thing, and combine it with conditioning stuff in some way, then I think you’d have a solid game plan. I just don’t think most of the neurotic folks that need to drop fat will do that; the meme “hard work equals results” is too powerful.

Conditioning Work Is Not Strength Work

One thing you will never see me do is suggesting “functional metabolic workouts” to someone interested in an improved physique. At least not exclusively.

This is all the rage these days, combining weights and conditioning into these “functional” [sic] circuits and metabolic conditioning workouts. This concept is based on the idea that you can just mix the two together and suddenly you’ll shred up and be in the best shape ever.

Not so fast. There’s one thing I always repeat to people: strength will always have the greatest effect on every other aspect of fitness.

Here’s a simple analogy to illustrate the point. Say you’ve got two guys talking trash about their squats. One guy maxes at 600 lbs, but never does more than 3 reps. The other guy only maxes at 450, but he regularly trains with very high reps and has done 15 reps with 400 lbs.

So they decide to have a contest to see who can do the most reps with 400 lbs. Who do you think will win?

If you went solely by specificity, you’d think it was the guy that trained for high-reps, right? To be completely fair, if you just took them out and put them in the rack to test it, the high-reps guy would probably win on that day.

But what happens if you give the stronger guy 3-4 weeks to work on high reps? Well, that 400 lb squat is only 67% of his 1RM. He might have tanked the first week because he’s out of shape, but here’s the confound: endurance trains up fast. Within 2-3 weeks, he’s gonna be capable of doing far more reps than his first try would suggest.

Why? It’s because strength improved his overall ability. Being strong doesn’t automatically mean that you’ll be able to knock off more reps with a given weight, but it does make it a lot easier to improve once you start training for it.

The lighter any given resistance (compared to your maximum ability), the easier it will be to improve your endurance with that resistance.

In contrast, focusing specifically on endurance only got that guy up to a 450 1RM – so not only is he weaker, but with just a few weeks of training his stronger friend managed to beat him on endurance too. It’s always easier to improve endurance than it is to improve muscle mass or strength.

So what happens when you do all these metabolic workouts in lieu of heavier, specific strength workouts? The net result is that you end up watering down both strength training and the conditioning sessions.

Does it save time? Probably. Does it make your clients sweat and feel like they did something useful? Almost certainly.

Unfortunately neither of those means it’s effective.

This is a mistake that even bodybuilders make, too. Going into a contest, what do old-school bodybuilders always do? They drop the heavy work and shift to high reps in order to “cut up”. In naturals, this is going to destroy your muscle mass.

To be fair, this is a case where individual goals come into the picture. If you’re training clients and the only goal they have is “drop some fat” and “have a hard fun workout”, then go hog-wild with the “functional” [sic] stuff. My advice is squarely aimed at people that want to drop fat while carrying an above-average amount of muscle and strength.

Organizing Everything

That last section now gives us some ideas on how to arrange things.

The biggest change I’d make from the current orthodoxy is to separate strength workouts and conditioning workouts. There’s absolutely no advantage to combining the two, beyond trying to save time. If you’re concerned about retaining muscle and strength on a diet, you need to separate the two.

I didn’t really touch much on how to incorporate HIIT and LISS methods, because I’ve written about that before here and here.

The only other things I have to say involve how to set up a routine that doesn’t overwork you, and to do that we can just invoke the old “high-low” approach. High-stress work should be concentrated on the same days, and separated by at least 48 hours. Low-stress work can be done on days in between.

For most purposes, a basic undulating periodization scheme is going to fit the bill. This is fancy jargon for saying “have some harder workouts and some lighter workouts each week”. An old standby, and what I used myself, is to have two days of strength work and two days of moderate conditioning work. If you want to do HIIT type stuff, do it on the strength days.

Normally I don’t think complex periodization schemes are necessary, but I think there’s a rationale for it in the context of trying to diet. The method I’ve been using during my recent dieting foray is based around a three-week cycle, moving from base percentages of 70%, 80%, and 90%, respectively, with goal reps of 5-6, 3-4, and 1-2 by week. There’s no fixed number of sets; instead I just set a brief time interval of 10-15 minutes and knock out as many as I can.

If the base starting weight feels too light, I can increase it. This is another case where the RPE scale comes in handy; if my starting weight is only a 7, then I can bump it up 5kg to get an 8-9. On the other hand, if I’m having a crappy day, I can also knock the weight back a little, too.

The third week cuts out the time limits and is more like a Max Effort session, where you can work up to a comfortable max. This creates a nice blend of heavy and light training, enough to keep gaining but not so much to burn you out; the auto-regulating stuff keeps you from overworking yourself.

Obviously I’m just using the bare minimum of exercises here, generally not much more than an overhead press + deadlift one day, then a squat + bench press the other, with a few sets of upper-back training thrown in afterward. Olympic lifts are recommended, but not mandatory; I used them both as a heavier strength exercise and as lighter conditioning work (though KB or DB versions would probably be better for this).

As mentioned, the weekly schedule is two “heavy” workouts (strength stuff, according to the cycle) and two conditioning workouts, which are basically just whatever. I’ve played around with weight circuits, kettlebells, Olympic lifts, and just plain-old cardio on the conditioning days.

If I wanted to do a three-day plan each week, I’d probably organize it by a heavy-light-medium schedule, with heaviest weights used Monday, 80% of Monday’s weights on Wednesday, and 90% of Monday’s weights on Friday. Do high-intensity conditioning on M/W/F, and then LISS cardio on T/Th/S if desired.

Now, there’s questions about doing four or more weight-sessions per week. I think with the proper diet this could be workable, as long as you kept each workout to a minimum. What I would not do is try to shoehorn a four-day upper/lower split in just because I felt the need to be doing something; unless you can scale back the volume and the effort of your sessions, more than three workouts is going to slap you down in a hurry.

Interval Training, HIIT, and Tempo Training for Fat Loss

As I mentioned in the last post on the role of anaerobic metabolism in fat-loss training, you’re definitely better off doing some kind of activity that’s more intense than light jogging on the treadmill for miles at a stretch. That is, if you’re specifically trying to improve body composition. If you’re training for a race or something like that, it’s a different matter.

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Anaerobic Exercise, EPOC, and Fat Loss

I was recently asked about the role of anaerobic metabolism in fat loss, and I figured that’s as good a topic as any to talk about.

For those unaware, your body has two basic ways of providing energy to your cells – one is oxygen-dependent, while the other can occur without oxygen. We know these are aerobic and anaerobic metabolism, respectively. We can further subdivide anaerobic metabolism into the phosphagen (alactic) pathway and the glycolytic (lactic-acid) pathway. Aerobic metabolism can occur both in oxygen-dependent or oxygen-independent modes; the latter tends to overlap with glycolytic metabolism.

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Fat Loss and Running

For some reason people seem to have the idea that running will create fat loss. There’s two ideas that probably contribute to this: the best runners are usually very lean, and the 1980s obsession with aerobics. The latter especially created a tradition so that “everybody knows” you go run or do aerobics classes to get in shape. Right?

As usual, it’s not that easy. There is some truth to the fact that steady-state aerobic exercise does tend to preferentially use circulating triglycerides as a fuel source (body fat, effectively). However as the current fad towards interval training will quickly remind us, the fuel source isn’t the entire story. There’s something to be said for shorter, more intense exercise. I won’t go into the details because they aren’t terribly important here, but maximal activation of anaerobic metabolism tends to chew up more calories and do favorable things for nutrient partitioning: calories go to muscle instead of fat storage, and more fat ends up being burned over a 24-hour period.

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Realistic Expectations

Have your mind right, the rest will follow

When people start weight training, they come in with a lot of pre-conceived notions. For the average raw newbie with the common if ill-defined motivation of “looking better”, most of these notions can be anticipated.

For men, they want a 6-pack set of abs. Women need to tone up the legs and firm up the butt.

Neither the average man or woman wants to get “too bulky, like the guys/girls in the magazines”.

In logic, it’s generally considered that if you start with a false premise, you will invariably end up with a false conclusion. If you’re in the gym busting ass and watching your diet like a hawk week in, week out, under the wrong idea, you’re probably not ending up where you want to be. A false premise has created the expectation of an outcome that doesn’t follow from what you’re doing.

Don’t get me wrong, I’m completely aware that the subjects of exercise and nutrition can get complex at times. Your job, be you beginning gym rat trying to figure things out or trainer trying to figure things out for people, is to reduce that complexity down to simple terms. It can seem like a daunting task.

The very fortunate reality of the matter is that, at the end of the day, it’s not that hard. While you’re being actively discouraged from learning and improving on your own by a fitness industry that needs your ignorance in order to profit, you can still make headway in this area.

Then we have the other side of the matter: how realistic is any given goal for you? As a newbie starting out, are you even asking the right questions? If your knowledge base is fundamentally skewed, how can you be?

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