If you’re trying to lose weight, the key is simply to reduce the number of calorie you take in, right? This has been the fundamental belief about weight loss for decades.
But a new study casts doubt on this principle. It suggests the body does not treat all calories the same, and that low carbohydrate diets may make your weight loss efforts more successful.
More often than not, people who lose weight gain at least some of it back within a year or two. Part of the reason for this is that weight loss brings with it a slower metabolism that burns fewer calories. Researchers with Boston Children’s Hospital and Framingham State University looked at the effect a low-carb diet had on dieters' ability to avoid regaining lost weight.
People eating the low-carb diet burned about 250 calories a day more than those eating the high-carb diet, which provided about 60 percent of calories from carbohydrate.
Next came the weight maintenance phase of the study. All the dieters were randomly put on a high-, moderate- or low-carb diet for another 20 weeks to compare how people eating different amounts of carbohydrates burned calories. The low-carb diet provided 20 percent of calories from low-sugar, whole grain carbohydrates, and calorie intake was adjusted for weight maintenance.
Over the course of the next four months, those eating the low-carb diet burned about 250 calories a day more than those eating the high-carb diet, which provided about 60 percent of calories from carbohydrate.
Participants who had the highest insulin secretion at the beginning of the study, evidence they were especially sensitive to eating large amounts of carbohydrates, had even more dramatic results from the low-carb diet. They burned an extra 400 calories a day.
Among people on the low-carb diet, decreased levels of ghrelin, the hormone that inhibits insulin secretion and increases appetite, were seen as well.
Processed carbohydrates, such as those found in low-fat cookies and snacks, that dominated grocery store shelves during the low-fat era have led to increased insulin levels in people, encouraging fat cells to store excessive calories. Fewer calories available to the body for energy increases hunger and slows the metabolism. Together, these are a recipe for weight gain.
The findings may not be the last word in the low-carb debate, but they are one more step toward understanding how to help the body lose weight and keep it off.
The study is published in BMJ.