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Caloric Deficit via Diet or Activity?

I had an idea that maybe the thing to do is to start eating for where I want to be weight and body comp wise, but when I started running the numbers via different BMR calculations, I realized that for a given LBM, BMR doesn’t vary much.

The Katch-McArdle calculation gives the same result for a given LBM regardless of total bodyweight. The Harris-Mifflin equation results in a difference of roughly 250cal for 237@24% vs 195@8%.

GIVEN that this is even a little bit accurate, AND that the biggest problem I’ve ever had is transitioning to a healthy maintenance diet, I had an idea.

MAYBE it makes more sense to start now eating right, enough protein, not too much fat, moderate carbs, calorie levels set by LBM, so as to develop the habit, and then adding activity/exercise beyond that which I’d normally engage in order to create a caloric deficit.

Then, as the body comp changes, I can scale back the activity and keep those things that I want to be a long-term part of my life, and that’s mostly just lifting heavy stuff.

I don’t post much, every couple of years I get a random idea. Any thoughts are appreciated.

Yeah, it’s the idea of G-flux. I pretty much agree with the idea, it is better for body comp to eat 3000 kcalories and burn 4000 kcalories than to eat 2000 and burn 3000 (that goes for maintenance and surplus calories too).

However, there are trad offs. More wear and tear. You get to eat more but at the same time you’ll be hungrier. It’s also vastly more difficult to burn a calorie than to not eat one.

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I’m not trying to be a dick here, but…

You’re big idea is to basically start eating better foods in the right amounts for your body and then continue that habit? And then add extra activity/exercise beyond that to get into a calorie deficit?

The second part of your post (where you scale back the things you dont like) is where everyone goes wrong, and why “diets dont work” and people “cant seem to lose the last bit of weight.” Generally speaking, if it takes you 4 days of lifting, and 2 hours of activity/exercise to look like X, when you scale back on the activity/exercise you are going to stop looking like X and look like “X minus 2 hours of activity”

Lonnie, I don’t necessarily disagree with what you’re saying.

Given that 195@8% == 179# LBM == 235@24%, and LBM is the only independent variable in the Katch-McArdle calculations, then for a constant level of activity, the maintenance calories are the same in both cases.

What I’m saying is that IF the above statement is true, then it seems to me smarter to set the diet according to the LBM, hold it constant, and adjust the TDEE upward in order to create a caloric deficit.

Then as the BW/BF% drops closer to the desired state, you reduce the caloric deficit by shedding activity back to the baseline of weights three days a week, and on the treadmill for 30 minutes every morning while on a daily conference call.

What I hear you saying, and what may in fact be true is that the equation is wrong, and it’s not really possible to be 195@8%on the same calories and activity as 235#24%.

I think that’s what I’m trying to get input on, whether the equation is true.

Those equations are just guidelines and should only ever be used to get a ballpark figure of where to start

If the equation says you will maintain body weight at 3,000 calories but you get fat in the real world… than go with the real world

This really is one of those things where you MUST experiment, track calories/amounts of food, and adjust accordingly


Great point. I’ll pile on by adding that the equations tell you a guideline for BMR, but not a guideline for how to change bodycomp.

The equations completely ignore the role of sleep, stress hormones, and environment on critical factors like insulin sensitivity.

Creating an imbalance thermodynamically (calories in vs. out) is a more important factor in people who are sedentary. Setting aside the issue of food quality, the more you create an anabolic millieu (sleep, micronutrients, hard training, metcon, etc.) the less your body comp will have to do with thermodynamics.

I know you aren’t saying this, but to take the calorie deficit model to an extreme, if fat loss was primarily thermodynamics, people could eat donuts and bacon up to their BMR, and spend half the day in an ice bath, and get lean.

Through experimentation (and good notes) I learned that I get leaner when I eat fewer carbs (total calories doesn’t seem to matter as much). However, that only happens if I am training hard enough, but not doing too much, where all the stress markers creep up. And the diet and training combo only works if my personal and professional life are relatively stable (long days are ok, but a crisis at work or at home always halts the leaning progress). Training and nutrition, crisis-free, only works when I am free of illness, injury, and pathogens. (For example, when the cottonwoods bloom here, I back off on the fat loss goals. I just try to maintain while I am in uber-histamine-land).

As an aside, I think part of the reason AAS work is that they can bypass these factors and keep the body anabolic.