-SIGH- A pessimist might say that the following news is another sign that Mother Nature sometimes has one mean sense of humor: Reducing your caloric intake in order to lose weight may, ironically, lead to weight gain.
How can it be that cutting intake creates more body mass?
Simple, say researchers the University of California at San Francisco: When you cut calories, you increase your body’s production of cortisol, the so-called “stress hormone,” which scientists have linked to the development of belly fat.
Although it’s frustrating to modern people, who have easy access to a reliable supply of food, cortisol was nature’s answer to the often feast-or-famine conditions of life among early humans. When food was not readily available, the stress created by concerns about finding it produced cortisol. The hormone then functioned as a sort of enforced savings plan that diverted the body’s resources to the creation of a fat stores in the belly.
Among modern people, cortisol can’t tell that a diet is an artificially induced food shortage, therefore sets about doing what it has always done-get the body to put on as much weight as possible in preparation for lean times.
The UCSF researchers tracked 121 women, whom they randomly assigned to four diet study groups:
- The first group restricted its calories to 1,200 per day and tracked their consumption
- The second group did not restrict its calories but did track consumption
- The third group restricted its calories to 1,200 per day but did not track their consumption
- The fourth group ate whatever number of calories its members normally consumed and did not track intake
At the end of three weeks, researchers found that the women who had been restricted to 1,200 calories daily had increased levels of cortisol and stress. They also found increased levels of stress in women who had been required to track their calories, regardless of the number.
They concluded that while tracking calories was stressful, it was the reduction of caloric intake to a low level that brought on cortisol and subsequent weight retention.
The discovery that cortisol is an important factor in weight control success leads to the question, if the key to losing weight is burning more calories than you take in, how do you lose weight without cutting down on calories?
One answer is to emphasize burning calories over restricting them. A diet that excludes physical activity (which reduces stress), or omits healthy foods (especially ones that give a sense of fullness), or does not take a long-range view, runs a low chance of success.
That latter factor means being patient enough to understand that weight gradually lost over months or a couple of years, rather than dramatically lost over weeks, is unlikely to come back. (The UCSF study, published in the April 6 online edition of Psychosomatic Medicine, says that while 47 percent of U.S. adults are on a diet at any one time, 64 percent of them will gain back more weight than they lose.)
So, what appears at first to be a trick nature is playing on earnest dieters may instead be a signal to change perceptions. It’s not so much how many calories you’re taking in, it’s what you’re doing to burn them up and put them to good use.
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Low-Cal Diets May Make You Gain Weight