Frosted Paleolithic Flakes

I think the paradox frog news has put me in a negative frame of mind. I've just finished chapter 6 of Keith Frayn's Metabolic Regulation: A Human Perspective, and had an irresistible urge to vent. Mind you, as an information resource it's a great book, but Frayn does tend to extrapolate the biochemistry with amazing tunnel vision, framed by health and nutrition dogma that itself has little supporting evidence.

I'm planning a larger post on the topics of carbohydrates, insulin, and fat storage when I finish the book, but what I just read sent me over the edge. Here's an excerpt:

First, imagine that the subject for this 'thought experiment' is sufficiently health-conscious as to eat a mainly carbohydrate breakfast: cereals and semi-skimmed milk, perhaps, but no bacon and eggs. Such a breakfast is likely also to be lower in energy content than a high-fat breakfast.

The disposition of glucose and amino acids will be much as described earlier, although there may be a sharper peak in glucose (and hence insulin) concentration, depending upon the amount and type of carbohydrate eaten. Release of non-esterified fatty acids from adipose tissue will be suppressed, leading to preservation of the adipose tissue triacylglycerol store.

What amazes me is that in this description of a "healthy breakfast", he's actually describing the potential development of obesity. The last sentence basically just says "insulin keeps the fat in the fat cells." Does it ever have a chance to get out? Maybe:

About an hour after this breakfast, our health-conscious subject sets out for some exercise - nothing strenuous, perhaps a swim or brisk walk for an hour, or even cycling to work . . . depending on how strenuous the exercise is, sympathetic nervous activity and increased adrenaline in plasma may gently switch on fat mobilisation in adipose tissue.

Note the qualification: "may gently switch on fat mobilisation", but only if the exercise is sufficiently strenuous. But how strenuous is strenuous enough? Is there some biological mechanism which notifies the conscious mind that you've exercised precisely enough to burn fat so you do not store excess, but not so hard that you will lose too much fat? Did the human body evolve eating some analogs of "cereals and skim milk"? And did our ancestors regularly exercise an hour after eating this breakfast?

So I think we can get some idea how much you need to twist what is known about the basic biochemical and cellular responses to food in order to support the current dogma of what supposedly constitutes "healthy eating". Maintenance of stable body fat stores following Frayn's description would require that a person precisely balance their carbohydrate intake and exercise after every single meal. In this scenario, metabolic regulation is not very robust, in the sense of maintaining the body's state over a wide range of conditions. Further, it requires a lot of conscious tracking of macronutrient intake and exercise.

Something tells me Paleolithic humans had bigger problems. Do you think perhaps evolution has solved this problem for us? Hmmmmm . . .