Low carb diets are very popular now. But do they really work? Can someone lose weight by severely limiting their carbs? A recent study indicates that they do work.
The study led by Boston Children’s Hospital, in partnership with Framingham State University, found that eating fewer carbs increases the number of calories burned. The study known as the Framingham State Food Study regulated what people ate by providing them with fully prepared food service meals for 20 weeks. Researchers tracked the participants’ weight and measured insulin secretion, metabolic hormones and calories burned. Out of 234 overweight adults participating, 164 achieved the goal of losing 10 to 14 percent of body weight and went on to the study’s maintenance phase.
The participants were put in three groups: high, moderate or low carb diets for the 20 week period of the study. Those on the low carb diet burned about 250 kilocalories a day more than those on the high carb diet. Among participants with the highest insulin secretion, those on the low carb diet burned about 400 kilocalories more a day. A hormone called ghrelin, thought to reduce calorie burning, was quite a bit lower among those on the low carb diet.
The study concludes that “lowering dietary carbohydrate increased energy expenditure during weight loss maintenance” which may “may improve the success of obesity treatment, especially among those with high insulin secretion.”
“This is the largest and longest feeding study to test the ‘Carbohydrate-Insulin Model,’ which provides a new way to think about and treat obesity,” said David Ludwig, MD, Ph.D., who is the co-principal investigator, in a statement. “According to this model, the processed carbohydrates that flooded our diets during the low-fat era have raised insulin levels, driving fat cells to store excessive calories. With fewer calories available to the rest of the body, hunger increases and metabolism slows — a recipe for weight gain.”
The lead researchers of the study recently launched a clinical trial evaluating 125 obese adults living in a residential center for 13 weeks. Participants are put in very low carb, high carb/low sugar, or high carb/high sugar diets. Results of the trial are expected in 2021.
Other studies have shown that low carb diets help overweight and obese people lose weight, plus improve their health. A 2003 study found that people with diabetes lost more weight during six months on a low carb diet than on a diet that restricted calories. A study two years later found that partially substituting carbs with either protein or monounsaturated fat can lower blood pressure, improve lipid levels, and reduce cardiovascular risk. Another study discovered that a low carb plant-based diet has advantages over a high carb/low-fat diet in improving heart disease risk factors.