In the last eighteen months of low-carbohydrate eating, I have completely enjoyed the freedom to eat any amount of food I desire. My experience has shown me that the body does indeed regulate its weight via hunger and satiety signals, but only when consuming the proper diet.
However, my freedom to consume has been abused on occasion. I can remember four times involving birthdays and barbecues, where I really packed in the protein. And each time I paid for that gourmandise in the middle of the night: waking up hot, sweating, and with a rapid pulse.
From what I have learned about our biochemistry on low-carb, I think this makes sense. When insulin levels are kept low, fuel calories cannot be stored, so the body has no choice but to burn them. Thus, the night sweats: you take in extra fuel, the motor runs hotter.
It occurs to me that had I wanted to avoid this midnight punishment for gluttony, there was always an antidote: dessert!
Yes, by ingesting a huge whack of sugar, I could trigger my pancreas to work overtime and flood my bloodstream with insulin. This would have the effect of pushing a large quantity of calories into my fat tissue, and spare me the mild overnight "food fever."
I am ready to believe that our custom of eating sweets at the end of a meal is a direct result of this phenomenon experienced by our ancestors. If one is fortunate enough to have a lot of extra food and access to sugar (the combination of which, about a hundred years ago was available only to the wealthy) it sounds like the perfect fattening plan. Now, I don't know if this is a biological "just-so story", but it makes sense to me.