NIH study finds varied responses to calorie restriction in obese adults
For the first time in a lab, researchers at the National Institutes of Health found evidence supporting the commonly held belief that people with certain physiologies lose less weight than others when limiting calories. (Study results published May 11 in Diabetes.)
Researchers at the Phoenix Epidemiology and Clinical Research Branch (PECRB), part of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases, studied 12 men and women with obesity in the facility’s metabolic unit. Using a whole-room indirect calorimeter – which allows energy expenditure to be calculated based on air samples – researchers took baseline measurements of the participants’ energy expenditure in response to a day of fasting, followed by a six-week inpatient phase of 50 percent calorie reduction. After accounting for age, sex, race and baseline weight, the researchers found that the people who lost the least weight during the calorie-reduced period were those whose metabolism decreased the most during fasting. Those people have what the researchers call a “thrifty” metabolism, compared to a “spendthrift” metabolism in those who lost the most weight and whose metabolism decreased the least.