How an individual’s energy expenditure responds to calorie restriction may predict weight loss when dieting in obese patients, according to data published in Diabetes.
In particular, researchers at the Phoenix Epidemiology and Clinical Research Branch (PECRB) of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) found that people with a “thrifty” metabolism may lose less weight than those with a “spendthrift” metabolism.
For their study, the researchers evaluated 12 obese men and women in their metabolic clinic. Using a whole-room indirect calorimeter, they measured participants’ 24-hour energy expenditure to fasting and to 200% overfeeding. Participants then underwent 6 weeks of 50% calorie restriction.
After accounting for age, sex, race and baseline weight, data indicated that smaller reductions in 24-hour energy expenditure during fasting and larger responses to overfeeding, which characterize a “spendthrift” metabolism, predicted more weight loss during the reduced-calorie period.
In comparison, people with larger reductions in 24-hour energy expenditure during fasting and smaller increases with overfeeding, which characterize a “thrifty” metabolism, lost the least weight, as compared with those with a “spendthrift” metabolism, who lost the most weight.
“When people who are obese decrease the amount of food they eat, metabolic responses vary greatly, with a ‘thrifty’ metabolism possibly contributing to less weight lost,” Susanne Votruba, PhD, study author and PECRB clinical investigator, said in a press release.
“While behavioral factors such as adherence to diet affect weight loss to an extent, our study suggests we should consider a larger picture that includes individual physiology — and that weight loss is one situation where being thrifty doesn’t pay.”
At this point, the researchers are unsure of how these biological differences arise, including whether they are innate or develop over time. More research is necessary to determine whether individual responses to calorie reduction can be used to prevent weight gain.
“The results corroborate the idea that some people who are obese may have to work harder to lose weight due to metabolic differences,” Martin Reinhardt, MD, lead author and PECRB postdoctoral fellow, said in the release. “But biology is not destiny. Balanced diet and regular physical activity over a long period can be very effective for weight loss.”
In the release, NIDDK Director Griffin P. Rodgers, MD, said these results suggest promise for more tailored treatment plans for patients with obesity.
“What we’ve learned from this study may one day enable a more personalized approach to help people who are obese achieve a healthy weight,” Rodgers said. “This study represents the latest advance in NIDDK’s ongoing efforts to increase understanding of obesity.”
The researchers now plan to study how lean people respond to increased caloric intake, according to the release.