A new study suggests that low energy intake combined with low energy expenditure may be a stronger predictor of future weight gain than excessive caloric intake.
Obesity is an increasingly serious worldwide health concern. In a recent fact sheet on Obesity and Overweight, the World Health Organization reported that, globally, 39% of adults over 18 years of age were overweight in 2014, and 13% were obese; moreover, most of the world’s population live in countries where overweight and obesity are credited with causing more deaths than being underweight.
Current models for weight management have tended to focus on excessive caloric intake as a key factor leading to obesity and being overweight. As a result, strategies combating obesity tend to focus primarily on reducing caloric intake (i.e., dieting), on the presumption that a pattern of energy intake which exceeds energy output (exercise) is the best predictor of long-term weight gain.
However, a new study recently published in the American Journal of Clinical Nutrition suggests that increasing exercise to match caloric intake, rather than dieting, may be a more effective strategy for long-term weight management. The study also suggests that a combination of low caloric intake and limited exercise may in fact be a greater predictor of future weight than excessive caloric intake.
The study involved two groups of participants – adolescents, and college aged women. In the first stage of the study, researchers collected data – including resting metabolic rate, body fat percentage, and energy intake and expenditure – about each participant over a period of two weeks. This data was then used to calculate two values for each individual:
- energy balance, which is energy intake minus energy output. This value gives a measure of how closely an individual’s caloric intake matches the amount of energy burned through exercise and activity.
- energy flux, which is energy intake plus energy output. This value provides a measure of the overall energetic-ness of the individual (i.e., high energy flux indicates a person who both consumes and burns high levels of energy).
After the two week period, annual measurements of body fat percentage were taken for the next 2 years (in the case of college aged women) and 3 years (in the case of adolescents).
Results of the study indicated that a low energy flux, more so than excessive caloric intake, was a predictor for future increases in body fat. This finding held true for both adolescents and college aged women. In addition, the study showed that having a high energy flux appeared to help prevent fat gain in part because it was associated with a higher resting metabolic rate.
On the other hand, energy balance did not appear to be correlated to whether an individual would gain weight in the future. This result may suggest that simply reducing caloric intake (dieting) to match energy expenditure may not be the best predictor of a future tendency toward overweight and obesity.
Based on this research, the authors of the study suggest that increasing energy expenditure, and maintaining a high overall energy flux, may be more effective for reducing body fat than controlling caloric intake.
Written By: Linda Jensen