Before you go any further with your New Year’s resolution about dieting read this:
Beyond the psychology of dieting and our largely inherited physiology, we’re still driven by the evolutionary pressures that drove our ancient hominid ancestors — hunters and gatherers, who had to make the most of every bite to survive. Sometimes their food was plentiful, but during times of scarcity, their bodies adapted by lowering their metabolism to conserve every calorie consumed. Following a period of scarcity, their bodies became even more efficient at storing fat in preparation for the next famine. These fat-layered bodies, better able to adapt to scarcity, were likelier to reproduce. As a species, therefore, we’ve inherited a predisposition to hold onto fat after each period of scarcity. Today, our bodies can’t distinguish between hunger caused by famine and hunger caused by a self-imposed diet — and they react to the latter as if it were the former. The “failure” of diets is actually a “success” in terms of species survival!
When dieting for weight loss, our bodies respond to the perceived famine by feeding off fat and muscle. Muscle is the metabolically active part of our body: the more muscle we have, the more calories we can burn. Since every weight-loss attempt includes the loss of both fat and muscle (but what’s regained is only fat), dieters burn even fewer calories, which makes it easier to gain weight and results in a higher fat-to-muscle ratio. Repeated dieting attempts may significantly increase the percentage of body fat over time. In fact, in 2007, Traci Mann and her colleagues at UCLA conducted a comprehensive and rigorous metanalysis of 31 long-term studies of obesity treatment for Medicare patients. They found that despite losing 5 to 10 percent of their starting weight in the first six months, the vast majority of dieters had regained all the weight — and within four or five years, one-third to two-thirds of subjects had regained more weight than they’d lost.