The first nasty take home is that we know nothing and clearly have it all wrong as far as our explanations go.
As far as weight management goes, exercise improves health but does little to regulate weight.
I do suspect that it is all about our lousy use of starches and sugars.
.Why doing more exercise won’t help you burn more calories
Metabolic minefieldFor those trying to lose weight, the body plays a cruel trick. As the excess comes off, your metabolism slows down, which can trigger that all-too-common phenomenon of gaining the weight right back. That was evident in the outcomes of 14 contestants on The Biggest Loser. Six years after losing nearly 60 kilograms on average on the TV weight-loss show, all but one regained some of it. Five were back to their original weight or more.
Similar signs emerge when comparing groups of three people matched by gender and weight: one at their usual weight, one having lost weight a few weeks ago and one having done so a year earlier. Those who lost weight, whether recently or a year prior, had slower metabolisms than those at their usual weights, raising the risk of putting the pounds back on. It is as if the body is trying to return the dial to the heavier, pre-weight-loss state.
There is a good reason for this, says evolutionary anthropologist Herman Pontzer at Hunter College in New York. The body evolved to make sure we store enough energy to find food and survive lean times. So if food intake drops in dieting, metabolism slows to try to preserve resources, and that effect seems to linger, even after your weight goes up again. “Evolution isn’t trying to give you a summer beach body,” says Pontzer. “Your body’s trying very hard to match your expenditure to what you bring in every day.”