Study: Cutting Calories Doesn’t Always Lead To Weight Loss
If you’re like many people, you’ve dieted repeatedly but you’ve never managed to lose much weight. Now, a recent study sheds some light on why that phenomenon occurs.
The study, published in the medical journal The Lancet, proved what many dieters suspected: cutting calories doesn’t work as effectively as dieters think it will. The problem appears to involve how your metabolism reacts to caloric restriction.
Drop 500 Calories Each Day, Lose … Less?
Many dieters – and most people who diet frequently or repeatedly – have heard the mantra that each pound is “worth” 3,500 calories. In other words, in order to drop one pound, you need either to eat 3,500 calories fewer over a period of time, or burn 3,500 calories more.
Most people use a combination of these approaches – i.e., they’ll drop 300 calories per day from their diets and attempt to burn another 200 calories a day through a vigorous exercise program. In theory, that should add up to a 500-calorie-per-day deficit – the equivalent of one pound per week or about 50 pounds per year shed.
However, in most cases, long-term dieters have found they simply don’t lose that much weight that quickly. The Lancet study found that same 500-calorie-per-day deficit would produce a 50-pound weight loss in three years, not one year. The bulk of the weight loss would occur in the first year, and then weight loss gradually would taper off over the next two years until the person reached a plateau.
Weight-Loss Problem Involves Metabolism
Most long-term dieters also are familiar with the concept that metabolism slows when you diet; your body goes into “starvation” mode, according to that theory, and holds on to your fat because it thinks you’ll need it. The Lancet researchers agreed with this theory, noting that your body’s normal reaction to a reduction in calories is a reduction in your metabolic rate.
More important, though, is the concept that people who weigh more need more calories just to keep their bodies moving through a typical day, the researchers said. When you lose weight, you gradually need fewer calories just to stay even, which means you’d need to keep reducing the calories you consume in order to keep up the same weight loss rate.
According to the study, adults who weigh more to begin with actually lose more weight at first than people with less body fat, but also take longer to reach a weight at which their weight loss levels out. Once their weight loss evens out, they must not revert to their pre-diet calorie levels, or they’ll begin to gain weight.
What Does This Mean For Dieters?
A study showing it takes a larger caloric deficit to lose weight over time may not represent welcome news to dieters. However, it helps to explain what almost everyone already knows: it’s very difficult to lose weight and keep it off.
In fact, the researchers reported in The Lancet that morbidly obese individuals – who represent about 14 percent of the U.S. population overall – would need to cut about 500 calories from their diets permanently in order to lose enough weight to return to the average body weight of people in the 1970s. Once they reached their target weight, they couldn’t begin to eat more or they’d gain some or all of the weight back.
It’s possible that’s the reason why people tend to regain weight – if you feel as if you’re on a “diet,” which implied deprivation, you look toward an “end” to that diet and a chance to indulge in the foods you cut to lose the weight. However, if you believe the researchers’ take on calories and weight loss, dieting means you can’t ever go back to that way of eating again.