A major new study could help more weight-loss winners keep off the pounds they've shed — if they can pass on the bread basket.
The research, published in the journal BMJ, found that among study participants who had just successfully lost weight, those who followed a diet with the lowest percentage of carbohydrates not only maintained their new, lower weight but also had a higher resting metabolism. That is, they burned calories at a higher rate when, say, they were sitting around watching TV than those eating more carbs would. That last detail is what has some experts excited about the results — calling them “profound” and potentially guideline-shifting — because it indicates a possible way forward for obesity treatments.
As the authors acknowledged in the study, such treatments have been difficult even for people working quite hard to follow them. “With weight loss, hunger increases and energy expenditure decreases — physiological adaptations that defend against long-term weight change.” Their work put participants into that challenging situation, since they’d lost 12 percent of their body weight in the 10 weeks prior to the start of the carb-measuring phase of the work.
In that phase, the 164 adult participants were given meals that featured either 20, 40 or 60 percent of their daily calories from carbs. (The percentage of protein was held constant for all.) From there, researchers measured total energy expenditure, resting energy expenditure, and related things like the levels of hormones such as leptin and ghrelin that aid in metabolism.