The person may not be eating too many total calories, just too many of the wrong type. My first question in such a case is always, What kind of weight are you gaining? Muscle mass? Bone density? Fat? And my second question is how they know which it is. Then, depending on the answer, my third question is often, How much carbohydrate are you eating? Plus I add a discussion of insulin resistance and its effect on our carbohydrate tolerance.
Low BMR is actually not a good thing in many cases, because it means that the body is not expending energy on such incidental processes as hair growth, the reproductive system, muscle growth, bone density, and so on, because it doesn’t have the reserves to deal with anything but basic survival. Exercise becomes impossible, and the person finds him- or herself continually hungry (to prompt an increase in energy intake) and lethargic (to save energy expenditure). The body conserves its precious fat reserve, saving it for emergencies. The body starts cutting muscle mass and bone density before depleting its fat reserves. Yes, the fat eventually does get consumed, but at a fairly late stage in the process of starvation. These are evolutionary adaptations developed over two million years of experience with alternating between famine and plenty.
It’s the low serum insulin resulting from a low-carbohydrate diet that permits fat to be mobilised and metabolised, insulin being the primary fat-storage hormone. To the extent that exercise consumes glucose and helps remove it from the bloodstream—thereby reducing the need for serum insulin—I’m sure it helps. Exercise also promotes mitochondrial healing, as long as we don’t keep damaging our mitochondria with high levels of serum glucose, and in that way helps promote metabolic health, which is necessary for proper fat metabolism. But the amount of energy expended by exercising is generally so small, compared with the caloric content of food, that exercise should not be regarded as a primary means of fat control. Check out one of those articles listing how much exercise is required to work off a bagel, a glazed doughnut, etc.
Unfortunately, it doesn’t appear to be going without saying, even on these forums, which is why some of us feel it necessary to keep saying it. The message of “eat less, move more” has been drummed into our ears for so long, that the habit of belief (as I call it) can persist long after we reach an intellectual understanding of how the body really works. Otherwise, “calories are important”/“no they’re not” threads wouldn’t keep cropping up regularly.
Actually, regardless of what people believe, the fat is present in a ketogenic diet in order to replace calories lost from cutting carbohydrate intake, and also because, once our need for protein is satisfied, fat is highly satiating in its own right. (Fat is also a safe source of calories, because its effect on insulin secretion is so minimal as to be negligible.) Raubenheimer and Simpson claim that people, like all mammals, have an instinct for how much protein they need, so protein intake is not a major focus of our advice on these forums—our recommendation of 1.0-1.5 g/kg LBM/day basically boils down to “eat a reasonable amount of protein,” and most newbies are already doing that.
From what I’ve learned, it appears that it is not protein that stimulates metabolism (since protein is primarily used for the body’s structural needs, being metabolised for energy only in extreme situations), but rather energy intake, which in a well-formulated ketogenic diet, is fat. The human body has mechanisms to regulate energy expenditure in accordance with intake, and is just as capable of ramping up the BMR in situations of abundance as it is of cutting the BMR in situations of scarcity. “Eating fat to lose fat,” is a catch phrase that Dr. Fung uses to move people from the low-fat, high-carb mindset into a healthier one, in which carbohydrate intake is greatly reduced, so that the resulting lower level of serum insulin can permit the mobilisation of fatty acids to be metabolised.
As I understand my reading, nitrogen balance is actually regulated by the uric acid cycle, in combination with the level of deaminated amino acids, which in a ketogenic situation is primarily the result of a serum insulin level low enough to permit the process of gluconeogenesis (by which amino acids are turned into the small amount of glucose that the body actually needs). Granted, there is a certain irreducible amount of deamination and nitrogen excretion occurring regardless of diet, which is why our need for protein is constant, regardless of the composition of our diet. Insulin inhibits the production of nitric oxide from the freed-up nitrogen, which is one of the reasons a high-carbohydrate diet often results in hypertension.
As for lipolysis—the breaking down of triglycerides into their component fatty acids and glycerol backbone—this can occur in adipose tissue only in the presence of low levels of serum insulin, as was demonstrated by Yalow and Berson in the last century. Insulin-like growth factor (IGF) has been shown to have a similar effect, and while I haven’t read anything about the effect of HGH on fat storage, I would expect it to inhibit lipolysis as well, or at best to have no effect on adipose at all.
Fatty-acid metabolism is also inhibited by elevated serum insulin, the idea being that the need to clear glucose from the body before it does damage takes priority, so glucose metabolism gets prioritised over fatty-acid metabolism, despite the advantages of fat-adaptation. Bikman has shown that adipose tissue can, in a low-insulin setting, “decouple” its metabolism of fatty acids from its actual need for energy, thus resulting in increased fatty acid metabolism and the wasting of excess stored energy (fat).
Taubes did the calculations, and assuming the estimate of 3500 (k)cals to a pound of fat is correct, an excess of 20 calories a day above energy expenditure, or a deficit of 20 calories below expenditure, will result in a net gain or loss of 20 lbs./decade. When left to its own devices (i.e., when we eat to satiety), the body does better than that, managing to match intake and expenditure almost exactly over any given eight-day period. I also find that, on those occasions when I eat past the point of satiation, my metabolism increases to compensate (I am sure that there’s a limit here, however). I don’t like to eat past satiety, because I then tend to find myself feeling extremely hot at night, and I really dislike soaking my pillows and bedsheets with perspiration.
It just goes to show how much power the standard governmental dietary advice has over our thinking. And besides, the CICO model isn’t entirely wrong; it’s just that it gets the arrow of causation wrong. As Gary Taubes points out, the reason we take in more (or less) energy than we should is because our hormones are in weight gain (or weight loss) mode, and this is controled by the composition of our food, not the quantity.
My favourite example is children during their pubertal growth spurt: sure, their energy intake is required to be greater than their expenditure, but that’s because their hormones are making them grow and causing them to eat more to fuel that growth. No sane person claims that eating our parents out of house and home is what causes our growth into adulthood, lol! As Taubes also points out, further evidence that the process is hormone-driven is seen by the fact that although boys and girls start out with similar body compositions, girls put on comparatively more fat, and boys put on comparatively more muscle. If hormones weren’t involved, all children would add weight in the same places, regardless of their sex.
Though that’s very little exercise, sometimes I think people are even lazier than me (well, no, I am very lazy but feel the need for some exercise. I suffer in complete inactivity).