That sounds good. But I disagree. Energy expenditure is a function of system size. As we lose weight, system size grows smaller. As the system grows smaller, its energy expenditure decreases accordingly. If we keep the same intake throughout, we eventually reach yet another homeostatic equilibrium. Weight loss stalls.

Now the question is, how do we increase energy expenditure, and maybe break a stall? Simple. Increase system size. Or increase Ein. Or both. Increasing system size is out. All that's left is increasing Ein. But we'll grow fat again. Only if that which we eat causes fuel to be shuttled to fat tissue.

The flip side is that the body becomes efficient with energy regardless of diet. This is the neuro side of things. As in neuro-muscular. That's partly why we can eventually lift bigger objects even though we don't have bigger muscles.

I forgot. During weight loss, the fat that is released from fat cells is added to total Ein. And affects Eout accordingly. Once the system reaches homeostatic equilibrium, i.e. stalls, this implies two things. That there is less fat being released from fat cells which reduces total Ein, and that Eout has decreased accordingly.

Seejay -- I'm trying to follow. (Preferably without, as was suggested, searching through years of posts.) This is actually the first time I've heard the claim that weight can be maintained without an energy balance.


This implies that fat calories weigh less than muscle calories?


This implies that muscle calories weigh less than fat calories?


This implies that muscle calories weigh less than fat calories?

I'm unable to piece together the logic. Perhaps it would be easier for someone to give me an example of a scenario where an individual can maintain a given weight long-term with either CI>CO or CI<CO. Note that by CO I mean every unit of caloric energy that is burned, whether it be by exercise, metabolism, any other function. Anything that is not burned must be stored (as weight), right?

BTW -- I'm aware that "a calorie is not a calorie" in terms of weight gain and weight loss, and that's why LC is the way to go. But we're talking about CI/CO and weight maintenance, which is a different thing entirely.

Only if we believe that's how it works. And only partly. We can also waste calories through various mechanisms. But that's still not how it works. It's the system that decides both Ein and Eout. When Ein increases, the system increases Eout to compensate. When Eout increases, the system increases Ein to compensate. And what determines both Ein and Eout is system size.

So what determines system size?

Touche on your point about wasted vs. burned. But waste would be included in CO. When a calorie comes in I only see two choices: 1) It stays in, as weight, and 2) It ends up, one way or another, as CO. What alternatives am I missing?

Maybe this will help clarify. From Chris Masterjohn:

So, you asked for an example of a long-term person who is weight stable, where CI doesn't equal CO.

If you define CO as the outcome of all CI, that is a tautology. It doesn't help choosing food, because calories are not the only property of food that makes a difference in both sides: income and outgo.

That seems to match what I said above: A calorie-in must either be stored, or must become CO. (The complex factors that determine which of these options occur for a given calorie don't seem relevant here.)

This still doesn't clarify how long-term weight maintenance is possible when CI != CO.

What determines system size? That's what we're missing. The answer is fuel partitioning. With calories, we only see the system as one unique system. With hormones, we see the system divided in several systems each of which can choose where the calories go. For humans, the system is divided into two major calorie dumps, fat tissue, lean tissue. By partitioning fuel either toward lean tissue, or toward fat tissue, we can increase, or decrease system size. But it's not (Ein - Eout) that decides where the fuel will go, it's the system, i.e. the hormones.

As the system partitions more fuel toward fat tissue, the system sees a caloric deficit in lean tissue, it calls for more fuel to compensate, we eat more. The system grows bigger because fat tissue has grown bigger, and lean tissue has remained the same size due to a compensatory increase in Ein. As the system grows bigger Eout has increased, the system increases Ein further to compensate. There is not just one increase in Ein but two. One for the caloric deficit at the lean tissue, and one for the increase in system size. If we maintain Ein the same, fat tissue will continue to grow bigger because there is still more fuel sent there but lean tissue will grow smaller (or decrease Eout locally) because there is still a caloric deficit there.

As more and more fuel is partitioned to fat tissue, and as the system grows bigger, and as Ein is increased to compensate, and Eout increases as well but perhaps more slowly, the system will eventually reach a homeostatic equilibrium and remain at a new stable size until fuel partitioning is changed again. And round we go.

So what controls fuel partitioning?

The person who figures out that mystery gets free sex for life.

I am saying, I agree with you, if you start by defining CI as equal to CO because weight is stable. That is the tautology part.

We could also see weight stable with CI and CO steadily and equally decreasing, or CI and CO steadily and equally increasing.

I have been stumped on this point too but I haven't found any studies done on glycogen utilization while on a low carb diet.

The body has three energy pathways though, you have ATP-pCR, which is anaerobic and only lasts a few seconds, then you have fast glycolysis which burns glycogen and produces lactic acid, then you have your oxidative chain which includes 2 different pathways the slow glycolysis which produces pyruvic acid and the electron transport chain and krebs cycle which uses fat, glucose, or protein.

If on LC the body didn't replenish muscle glycogen then you wouldn't use the fast glycolysis chain but that would mean no lactic acid build up, which isn't true. Lactic acid is the burn you get from lifting a weight to failure, its still there. So either the body is replacing glycogen my manufacturing glucose in the liver or there is another pathway that also produces lactic acid that uses fat that we don't know about. Either way there is no evidence for either AFAIK.

Oh and its a mistake to assume CI = CO because not all macronutrients are used for energy creation and you can't assume all macronutrients get 100% digested or aren't excreted when present in excess.

It's not that we haven't thought of it. The first premise of LC is that Cal-In Cal-Out is sabotaged by unrelenting hunger unless insulin is brought low by low carb. Ok, you've heard that right? And I'll add that the second premise is that if one has normal metabolism, undamaged by high carbs, then a person will not be overweight almost no matter what, because he will loath food when he has eaten too much. This is true even if he eats sugary junk. Until the damage sets in. Most of us here have in common that we want a way to stay at the "normal" weight with a metabolic fix rather than through a regimen of diet and exercise. It's not like we haven't tried both countless times you know.

Many if not most of us remember a time in our youth when we ate whatever we wanted whenever we wanted and didn't gain an ounce. We were gluttoness over the widest variety of junk foods yet perfectly smug that we were not like those other people who put on weight. That was before we messed up our bodies' abilities to know when it needs food or not.

And by the way, I agree that a stall is "reaching a steady state". And if this steady state is 20 or 50 or 100 pounds higher than it should be? Some of us conclude that it is because a metabolism once damaged does not just fix itself overnight, if at all. Nevertheless we look for the method that will at least get it somewhat closer to health than it was when we started.

And then comes all the controversy over how to accomplish this. And this is much of what we argue over.

Agreed -- so we're on the same page. I'm not sure what even started this then. The above is how I interpreted doctorK's original comment, so I was surprised to see disagreement. Maybe I misread.

It is clear what he meant.


That the body (or every single living thing that has ever existed on the face of this planet) wastes energy is a big shock to some people. Reading the diet books that are the subject of discussion here helps a LOT.

Sure. I mean I had a friend who lose 170 lbs on low carb. She had several long stalls during her journey, and one several-month stall was finally broken when she increased her daily calories from 1400/day up to about 1800/day. OK, perhaps at the lower weight she was in a CI=CO stasis. But clearly *increasing* her calories to break the stall would see counterintuitive to many who spout the standard weight loss dogmas.

Yep, and he was absolutely correct: weight maintenance means CI=CO. So what precisely is your issue? (Maybe try relaxing and smiling for a moment before responding.)


No argument there. But we're talking about weight maintenance, not weight loss.