Bodyrecomposition Mailbag 4

Having written about what calories are, it’s time to return to the mailbag since this is always an easy way for me to get content.  Today I’ll address questions about heart rate monitors and metabolic rate, agronomist activity levels and calorie levels, NEAT and adaptive thermogenesis,  and then a long answer on the topic of whether to lose fat or gain muscle for a beginner at 20% bodyfat (if I were a different kind of writer I’d that THE ANSWER WILL SHOCK YOU!).

Heart Rate Monitoring and Metabolic Rate

Hey Lyle, Huge fan of your work, it really has changed my life… just wish I’d stumbled upon you a decade ago, I’d be a machine by now! Anyhow, I was just curious about your opinion on heart rate monitors and wether they can be an accurate way of monitoring your metabolism during a cut. I have a Fitbit charge hr which seems to do a pretty solid job. I.e. When I use it to cut I lose weight, bulk I gain weight and my weight is pretty damn stable when I use it to maintain. I’ve noticed that when I cut my resting pulse rate progressively gets lower over the course of the cut and also that I start to burn less and less calories during my workouts.


In at least a general sense, a drop in heart rate is pretty normal with dieting to lower levels.   For example, in a recent study that attempted to mimick the classic Minnesota Semi-Starvation study, men first overfed for one week before were placed on a 50% calorie reduction for three weeks.  In addition to changes in other metabolic parameters, heart rate went up from 65 to 68 Beats Per Minute (BPM) during overfeeding and dropped to 59 BPM during calorie restriction.    In a yet to be unpublished case study of contest dieting in a male bodybuilder, heart rate dropped by 9 BPM over 16 weeks along with metabolic rate and other hormonal factors.  Given that sympathetic nervous system output declines on a diet, and this is certainly part of the control of resting heart rate, this makes a great deal of sense.

So yes, it is at least qualitatively indicative although I’m don’t think you can use it to quantify how much metabolic rate has dropped specifically.

Assuming you want to be more quantitative, a better method would be to track morning body temperature since this too also decreases during dieting.  While you have to have a baseline morning temp before starting a diet (as the idea of a single normal body temp is incorrect), you can estimate that a 1 degree C drop in morning temperature (1.8 degrees F) is worth about a 10-13% drop in resting metabolic rate.

So say your RMR was estimated at 11 cal/lb (average value for males) and you weighed 180, that would be an RMR of 1980 (call it 2000) calories.   If your morning temperature reading dropped by 1 degree C, that would be a 10% reduction or 200 calories.  There would also be additional changes in exercise energy expenditure and potentially NEAT but those are very difficult to quantify.

Hope that helps.

Agronomist Activity Levels and Calorie Intake

Lyle, I never have had much help with bodybuilding nutrition and I would be thrilled if you might be able to answer a few of my questions. 1. My goal is to be 8-10% body fat currently at 15-18% 212 pounds 2. My work requires me to burn around 4400 calories (agronomist in college) So I have been now eating 3200-3400 calories a day from 320g protein 220g carbs (I use a Fitbit to calculate) My questions are am I eating the right amounts of food? I have read some of your articles that say carbs could be as low as sub 100g a day but would I be burning Too many extra calories?


Ok,between this and a recent exchange I had someone who coaches table tennis, I’m finding all kinds of new worlds.  To be honest, I had to look up what an agronomist was.

With that level of work related activity, I suspect that 3200-3400 calories is too low.  I mean, at 212, the quick estimate of your RMR is about 10-11 cal/lb or 2100-2300.  I’ll assume that your school is the only activity that you do and that takes your maintenance to 6700 calories.  It’s hard to imagine you do much activity beyond that but training won’t really add that much.

3400 calories is about a 50% deficit.  That is sustainable, my Rapid Fat Loss handbook generates deficits in that range although it will depend a lot on the intensity of the, err, agronomy (?) work. If it’s very low, that might be fine although big deficits and lots of activity often don’t go well together.   In this case, a more moderate 20-25% deficit from your maintenance might be a better place to start.

6700 calories/day *0.20 to 0.25 = 1340-1675 calories/day which is still pretty damn enormous.  I mean, that would predict OVER two pounds fat loss per week.

It would put you at 5360-5000 calories per day (good lord, this is Parillo level dieting, just let that go).

Your protein looks more than fine and might be a touch excessive but it probably keeps you full.  So far as carbs, yes, the 100 g value is a minimum but it will really depend on how intense the stuff you’re doing at school is.  If it’s mostly low intensity for extended periods, you don’t need a ton of carbs.  That said, at 5000 calories/day, if you don’t eat carbs and protein is at 1500 calories, that’s 300 grams of fat.

In this case, I think moderate carb/moderate fat approach will probably be best and I’ll base this on 5000 calories/day.

So protein is at 300 grams, that’s 1500 calories which leaves 3500 calories.  If you go 30% fat that’s 1050 calories divided by 9 calories per gram of fat or 115 grams of fat.  That leaves 2450 calories for carbs (5000 – 1500 – 1050 calories = 2450 calories) which, at 4 cal/g is 600 grams.

Which sounds insane but would fit at that deficit.  If you use a higher deficit, say 35%, just rerun the above calculations with protein at 300 grams, fat at 30% and the rest carbs.

So here’s what we learned from this question: Work in a field 8 hours/day while in school and you too can diet on 5000 calories per day.

Is NEAT Part of Adaptive Thermogenesis

Is the drop in NEAT a major part of what contributes to adaptive thermogenesis? Or is that something separate?


Ok, for readers not familiar with the term, NEAT refers to Non-Exercise Activity Thermogenesis.  Originally it was thought to represent only unconscious behaviors such as switching from sitting to standing, fidgeting and a few others.  In the earliest study, changes in NEAT in response to overfeeding had a direct effect on the amount of fat gained by any given person: the more their NEAT went up, the less fat they gained.

In more recent years, NEAT has come to encompass conscious activities and you can think of it as the calories burned in any activity that is NOT formal exercise.  Walking to the store from your car?  NEAT. Cleaning the house?  NEAT.   Climbing stairs instead of using the elevator?  NEAT.  Doing 60′ on the elliptical?  Formal exercise.

Now NEAT is turning out to be critically important and is becoming to be recognized as THE primary difference in daily energy expenditure for most people.     Differences in RMR are fairly tiny, differences in TEF are fairly tiny and unless they are doing tons of formal exercise, differences in TEA is irrelevant.  If these terms are Greek, read this and come back.

And differences in NEAT turn out to vary about 2000 calories between any two individuals.  This is not tiny.  So someone who is highly active, perhaps walking for a job (or doing any type of manual labor) may be burning stunningly more calories than someone who works in an office at a computer and goes home and sits on the couch.

Which is a long way to get to the answer.  We know that, when dieting, all components of energy expenditure decrease although they do so for two fundamental reasons.  The first is that the person is smaller.  A smaller body has a lower RMR.  Eating less food lowers TEF a bit.  If someone is exercising, a smaller body burns less calories during exercise; as well some people are less motivated to exercise on a diet.  And not only does a smaller body burn less calories during NEAT, the amount of NEAT often decreases when people diet.

H0wever, none of those changes are, strictly speaking, Adaptive Thermogenesis (AT).  Rather, AT refers to a drop in energy expenditure greater than would be predicted based on the change in weight.  For example, say that losing 10 lbs would predict that RMR would go down by 100 calories.  But when you measure it, it’s actually 150 calories.  That extra 50 calories is AT.

And in the strictest sense, a decrease in the amount of NEAT doesn’t fall under the umbrella of AT.  That said, there are other changes in the system that probably do.  For example there are changes in the efficiency of muscles and they may burn 10% less calories than would be predicted due to the change in bodyweight during formal exercise.  The same is likely to occur which means that calorie expenditure from NEAT can technically drop for three reasons: a lower bodyweight, doing less of it, and changes in muscular energy efficiency.  But only the last bit would be considered AT.


Best Approach to Increasing LBM with Higher Bodyfat

Hi Lyle, I used to weight close to 300 pounds and have gotten myself down to 160 pounds. However a lot of this weight loss was achieved early on following very poor dieting advice. This resulted in losing a great deal more muscle mass during the dieting process than if I had followed appropriate guidelines from the start. As consequence, I now have what feels like a rather high fat percentage (18-20%) for my lean body mass (128-133 pounds). The internet-at-large generally calls this state “skinny fat.” My question is whether I should continue to bring down my body fat % to close to 10-12% while minimizing muscle loss (to improve calorie partitioning during the anabolic phase) or bulk now until my lbm reaches a more robust level and then diet again. I tend to think the former is the more appropriate but bro-advice is all over the place. Would you also give me some general training/dieting advice to accomplish whatever the right approach is? Best, Max


The short-answer to this is that you are in one of the semi-rare situations where you can gain muscle while continuing to lose fat with a fairly simple approach that I’ll talk about when I get done babbling.

The longer answer is this: there is a general link between bodyfat percentage (BF%) and what is called calorie partitioning.    A dude named Gilbert Forbes wrote about this fairly endlessly back in the day and found that initial BF% had a huge impact on what was lost during dieting and what was gained during overfeeding.  Simply, the higher the BF%, the less lean body mass (LBM) was lost and vice versa (lower BF% -> more LBM loss).  And the lower the BF%, the more LBM was gained during overfeeding and vice versa (higher BF% and less LBM gained).  Thus is the balance of the universe maintained.

Let me know that the above was all derived on inactive people and a new study on athletes found that the Forbes predictions don’t hold well for athletes.  Because training changes the game as does sufficient protein.

However, he was also looking at people who were relatively naturally lean in terms of that second bit and this is where people have gone wrong in the real world.  We know that dieting down to a lowered bodyfat causes adaptations that tend to cause preferential fat gain when people gain weight again.  So while the Forbes data is compelling, it doesn’t mean that logically getting leaner and leaner will make you gain more LBM when you gain weight.  It’s actually the opposite or post-contest physique athletes would gain LBM at an accelerated rate.  And it’s the opposite.

That said, I have suggested myself that people pick a moderate BF%, about 10-15% for men (which is roughly 20-24% for women or thereabout) to alternate their gaining and dieting phases.  Which brings me the long way to your question which is, at 20%ish bodyfat, should you continue to diet given your low LBM.

And here the answer is, no.  You are in a semi-rare situation where you can gain muscle while continuing to lose fat.   I have written about this topic before and while people want to continue to hold onto the belief that it can always happen to one degree or another, the reality is that folks carrying MORE FAT with relatively LESS MUSCLE have the easiest time (there are other situations, powerful drugs and people returning from a layoff but this isn’t you).

This is due to the simple fact that it’s easier to lose fat when you’re carrying more combined with the fact that your relatively more untrained muscularly.  And you always gain muscle faster when you’re newer to weight training then when you’re more advanced.

Basically, fatter and untrained can do this fairly easily (I’ll tell you how in a second) while an advanced male at say 12% bodyfat trying to diet down while gaining muscle is unlikely to do it.  He wouldn’t gain muscle easily in the first place and sure as hell won’t dieting down.

In  this vein, let me address one of the papers that is commonly brought up to argue against that.  It was done by Garthe in relatively advanced athletes where one group used a slow rate of fat loss and another a fast rate.  The slow rate of fat loss group lost fat while gaining some LBM (note that the study used women and men and the women skewed the numbers towards LBM gain).  Aha, you say, trained athletes can do it.  Well, yeah but a couple of caveats.

First, for athletes, the average BF% was pretty high.    The men averaged 17% bodyfat and the women 27%.    So not really that lean relatively speaking.

Second and most importantly, many of the athletes gained mostly muscle in the upper body and these were athletes who did not typically resistance train the upper body.  Basically, they were upper body muscle noobs.

So they were carrying relatively more fat and were untrained in the muscles that made gains.  My point she is made.

Anyhow, as someone carrying more fat who is untrained, you can achieve this magic trick and here’s how: combine a moderate calorie deficit with plenty of protein and proper resistance training.

A recent study did this exact thing: put overweight men on a 40% deficit with either 1.2 g/kg or 2.4 g/kg (0.54 or 1.1 g/lb) bodyweight which was combined with resistance training and high-intensity interval training.  And while the 1.2 g/kg protein intake prevented LBM loss, the 2.4 g/kg group gained LBM while losing fat.  Mind you, it wasn’t a ton of muscle, about 2-2.5 lbs while losing nearly 10 lbs of fat but it was more than the lower protein group.

So that’s it.  If you’re not lifting, start with my beginner weight training series and then set up a diet with at least 1 g/lb of protein and some sort of deficit.  It can be a big one like in the study or more moderate if you prefer. some cardio on off days and you should see body recomposition, gaining muscle while losing fat.   Once you get leaner or a bit more well trained, you may need to move to specific cycles of gaining muscle and losing fat but for now, do them both.



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