4

votes

How does setpoint theory work if adipose tissue doesn't significantly affect BMR?

Answered on August 19, 2014
Created April 08, 2012 at 12:30 AM

Assume a man weighs 200 lbs (30% body fat) and is eating maintenance calories. He adopts a lower food reward diet (or whatever is your preferred method to lower setpoint) in order to change his body fat setpoint to 10%. Going from 30% to 10% body fat, would take him to 155 lbs.

My understanding of setpoint theory is that the change in diet would spontaneously cause him to naturally consume the maintenance calories of a 155 lb. man instead of a 200 lb. man. This would be less calories than he was previously eating, so he would lose weight (fat) over time until reaching equilibrium at 155 lbs.

However, I believe BMR is primarily determined by lean body mass. 200 lb. man at 30% and 155 lb. man at 10%, both have 140 lbs of lean body mass, so wouldn't they have roughly the same BMR. And if his activity level stays the same, wouldn't maintenance calories also stay the same?


I think I could have been more clear in my question. Let me clarify, and sorry if this gets long. I think I am about 15-20% body fat (e.g., can see top 2/3 of abs but not bottom). I have been quite strict paleo (archevore) for about 1.5 years. I never had an issue with obesity and can't imagine my leptin/insulin signaling is majorly off. I know my current weight is likely "healthy," but I would still like to get my body fat % down lower. I understand the other benefits of paleo (better digestion, sick less often, hopefully lower future risk of disease, etc) are far more important, but I can't help my vanity. Originally, I was resistant (though not militantly so) to the food reward hypothesis:

http://wholehealthsource.blogspot.com/2011/10/case-for-food-reward-hypothesis-of.html?showComment=1317598175219#c5238569267927826664

http://wholehealthsource.blogspot.com/2011/10/case-for-food-reward-hypothesis-of.html?showComment=1317769974737#c970352943858064614

I have since come around as it does seem to do a good job of explaining why so many very different diets can all result in significant weight loss. So, I am testing it out on myself and trying a lower food reward diet. I am eating only beef stew (pastured beef, potatoes, carrots, celery, tomatoes, spices, water in slow cooker). Plan is to try to do it for 2 weeks (currently on day 5) and reassess. I know such a limited diet may not be a good idea long-term. It seems to be working well as I am now naturally eating 2 bowls twice per day and generally feel quite satiated. My energy level is good (still lifting weights, running, etc.).

I want to get an estimate of how quickly I should expect to lose fat, but I find this hard to do directly for 2 reasons: (1) It is difficult to calculate how many calories I'm eating because I buy my beef locally from a small operation so there are no nutrition facts to tell me what % fat is in each cut and (2) It's even harder to accurately measure how many calories I burn each day. So, I was trying to find another way to estimate how quickly I should expect to lose fat. I recently read Richard Nikoley's blog post on food reward:

http://freetheanimal.com/2012/02/synthesis-low-carb-and-food-rewardpalatability-and-why-calories-count.html

and I tried applying his methodology. E.g., my current weight is 160 lbs at 18% body fat (29 lbs of fat) and if this new diet will get me to my "ideal" body fat % (e.g., 10%), then I'll end up weighing 156 lbs. So I plugged both into BMR calorie estimator to figure out how much lower my daily caloric requirement would be at new weight, which would in theory tell me how much fewer calories I'm eating each day. Unfortunately, I quickly realized that daily caloric requirement is about the same because lean mass stays the same (assuming mostly fat is lost). This makes me question my understanding of the theory.

After reading the comments below and the linked postings, I think maybe the answer is just that I'm misunderstanding how this actually works. Perhaps the answer is just that at the lower setpoint, the body starts burning more stored fat which causes you to eat less calories. Once the setpoint is reached, the body backs off on burning extra stored fat and you go back to eating more calories to maintenance level. To me, this makes sense, but still can we estimate how much stored fat we'll burn off per day? Would different diets (e.g., varying levels of food reward) make this happen faster or slower?

I realize many on here get annoyed with the "how do I get a 6-pack questions," so I apologize for that piece, but I really am trying to get a layman's understanding of how this works.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on April 09, 2012
at 02:10 AM

Hmm. I guess it can't be closed.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on April 09, 2012
at 02:09 AM

Upon further reflection, I guess my original question really has no valid answer, though the discussion has helped my understanding. Voting to close.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on April 09, 2012
at 01:25 AM

Interesting. I was going off sites like (for example): http://en.wikipedia.org/wiki/Basal_metabolic_rate#BMR_estimation_formulas http://www.exrx.net/Calculators/CalRequire.html But I guess we question all other conventional wisdom, so why not this as well.

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on April 09, 2012
at 12:43 AM

Thanks for all the responses so far. Edited to try to better clarify my question.

510bdda8988ed0d4b0ec0b738b4edb73

(20888)

on April 08, 2012
at 08:00 PM

Yeah, you said is a bit better than me. I do hate the term "set point". Coming from a chemical kinetics background, I just view it as the "equilibrium" of a complex set of differential equations (and we don't know that those equations are right now)

00c8eb3f6e6a1884216044ca29cf868a

on April 08, 2012
at 06:08 PM

mike: I agree with you. Here's my take on it, from a different angle (and shorter :) http://paleohacks.com/questions/97222/anyone-else-have-issues-with-the-concept-of-a-fat-setpoint

518bce04b12cd77741237e1f61075194

(11577)

on April 08, 2012
at 03:11 AM

Okay, but what about the fact that a heavier person is literally carrying a considerably larger quantity of mass? Everything I've learned in class (but that's conventional nutrition, so maybe just the demons talking) says that the larger you are the more energy it takes to just keep basic things happening (heart, circulation, respiration..). That's one of the forces behind the fact that the larger you are, the safer it is to lose weight at a rapid pace initially, and then it slows down as you reach a level where the calories you are eating are actually enough to reach a stable weight.

510bdda8988ed0d4b0ec0b738b4edb73

(20888)

on April 08, 2012
at 01:45 AM

ah, here's the link to the original answer that I was thinking about: paleohacks.com/questions/96181/how-can-i-permanently-lower-my-body-fat-set-point/96312#96312

1edb06ded9ccf098a4517ca4a7a34ebc

(14952)

on April 08, 2012
at 12:54 AM

I think that's why low carb is good for dropping fat, but once you're lean, low carb is nearly impossible.

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3 Answers

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510bdda8988ed0d4b0ec0b738b4edb73

(20888)

on April 08, 2012
at 01:45 AM

I wrote an answer to a similar question to this a while ago, but there's not a good enough search function here for me to find it. But (from my conclusions from what I've read) there's not so much of a set point as there is a settling point. A set point is like a thermostat, you set your room at 68 degrees, and if it's hotter the AC comes on and if it's colder the heat comes on. In your body, that implies that there's something that "sets your weight at 200lbs" and if you go lower than that you're hungry, and if you go over that you don't get hungry. I don't think that's the case.

I view it more like there's lots of different inputs and different outputs and your weight is a result of the interaction of all of those different signals. Let's start simple and slowly add a little complexity.

I'll start with insulin (remember, these are all simple examples, so no one flame me for leaving all the details out): you eat carbs (glucose) and your pancreas sees it, so it turns on the insulin which is a signal to tell your fat cells to pull the sugar in and store it. So you can have pretty good control over your weight by managing carbs: eat more carbs -> release insulin -> store fat / eat fewer carbs -> no insulin -> release fat. However you may have the control but you could be miserably hungry.

But that's just one signal, you may be able to adjust the fat storage, but how do you affect hunger?

Well it turns out that leptin is used as a hunger signal. Leptin is made in the fat cells, so more fat equals more leptin. When your brain sees leptin, it's supposed to turn the hunger off, when you're running low on fat stores, there should be less fat to make less leptin and your brain sees that and turns on the hunger. So there's a second signal.

Those two (insulin and leptin) working together should regulate hunger and fat storage which will gives the impression of a set point. But when someone gets obese, it's not that something happened to their set point, it's that the things listening to the signals don't work.

It (probably) starts with insulin resistance, after eating too many carbs (and in particular fructose), your fat cells stop listening to the insulin signal, so your pancreas pumps more and more out to get them to listen. In the same way, you store more and more fat and your brain starts to ignore the leptin signal and tells you to be hungry so you eat more. There's no "set point" there's just mishearing of signals.

That's why neither Taubes (insulin) or Kruse (leptin) is solely right here. It's a mix of signals. Often, though, fixing one can cause dramatic shifts that implicitly fix the others. Taubes, suggests managing it by controlling the insulin through carbs; Kruse says control the leptin with his leptin reset rx. But in real life it's a combo of those two (plus lots of other feedback mechanisms).

In the end, I probably didn't do a good job answering your question, but I don't want you to think about set point, it's more of a collection of lots of (known and unknown) feedback mechanisms. Rather than worrying about fixing a set point, try to control what we know about (insulin and leptin are the best understood right now) and see how it works for you. Personally, I don't worry about leptin, I control everything through insulin and carbs. But that doesn't mean I'm a low carb zealot who thinks you can't do it any other way.

510bdda8988ed0d4b0ec0b738b4edb73

(20888)

on April 08, 2012
at 08:00 PM

Yeah, you said is a bit better than me. I do hate the term "set point". Coming from a chemical kinetics background, I just view it as the "equilibrium" of a complex set of differential equations (and we don't know that those equations are right now)

00c8eb3f6e6a1884216044ca29cf868a

on April 08, 2012
at 06:08 PM

mike: I agree with you. Here's my take on it, from a different angle (and shorter :) http://paleohacks.com/questions/97222/anyone-else-have-issues-with-the-concept-of-a-fat-setpoint

510bdda8988ed0d4b0ec0b738b4edb73

(20888)

on April 08, 2012
at 01:45 AM

ah, here's the link to the original answer that I was thinking about: paleohacks.com/questions/96181/how-can-i-permanently-lower-my-body-fat-set-point/96312#96312

1
22424c9eef944ade83d4e4ffda907056

(1402)

on September 07, 2013
at 12:44 AM

I'm pretty sure that your assumption that BMR is determined by lean mass is incorrect.

This isn't solid evidence by any means, but here's an article on Mark's Daily Apple: http://www.marksdailyapple.com/how-many-calories-does-muscle-really-burn-and-why-its-not-about-calories-anyway/#axzz1rVA8iy2Y

Ae8946707ddebf0f0bfbcfc63276d823

(9402)

on April 09, 2012
at 01:25 AM

Interesting. I was going off sites like (for example): http://en.wikipedia.org/wiki/Basal_metabolic_rate#BMR_estimation_formulas http://www.exrx.net/Calculators/CalRequire.html But I guess we question all other conventional wisdom, so why not this as well.

-2
1edb06ded9ccf098a4517ca4a7a34ebc

on April 08, 2012
at 12:54 AM

I'm not an expert but I thought food reward worked a little differently than you explained. Also, I beleive that the leaner you are, the higher your energy requirements are. For a lean person to run a 100 yard sprint is a lot more demanding than an overweight man b/c the lean person has less (endogenous) reserves to mobilize for energy, so they need more (exogenous) food energy. That is why the leaner you are, the more carbs you can handle. At least, I think that's how I remember it working. Does that make sense?

1edb06ded9ccf098a4517ca4a7a34ebc

(14952)

on April 08, 2012
at 12:54 AM

I think that's why low carb is good for dropping fat, but once you're lean, low carb is nearly impossible.

518bce04b12cd77741237e1f61075194

(11577)

on April 08, 2012
at 03:11 AM

Okay, but what about the fact that a heavier person is literally carrying a considerably larger quantity of mass? Everything I've learned in class (but that's conventional nutrition, so maybe just the demons talking) says that the larger you are the more energy it takes to just keep basic things happening (heart, circulation, respiration..). That's one of the forces behind the fact that the larger you are, the safer it is to lose weight at a rapid pace initially, and then it slows down as you reach a level where the calories you are eating are actually enough to reach a stable weight.

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