Many people struggling with obesity find it difficult to lose weight despite engaging in regular exercise. This is because their resting metabolic rate decreases significantly with additional physical activity. A new study conducted by an international team of scientists, including researchers from the Chinese Academy of Sciences, has shed light on this phenomenon. The study, published in the journal Current Biology, analyzed data from 1,750 men and women to determine the impact of exercise on their total energy expenditure. The researchers found that only 72% of the extra calories burned during exercise contributed to the overall energy expenditure for the day. The remaining 28% did not show up in the daily energy balance, as the body compensated for the increased energy demand during exercise by reducing the resting metabolic rate.
The study also found that this compensation was most pronounced in people with obesity. In these individuals, only 51% of the calories burned during exercise contributed to the daily energy expenditure, as the body reduced the resting metabolic rate by half a calorie for every calorie burned during exercise. This explains why people with obesity often struggle to lose weight despite engaging in regular exercise. The researchers suggest that if this energy compensation has a genetic basis, it may be possible to identify individuals for whom exercise is not a useful addition to their diet.
The study’s findings have important implications for weight loss strategies. While exercise is still an important component of a healthy lifestyle, it may not be sufficient for weight loss in people with obesity. A combination of dietary changes and exercise may be necessary to achieve a calorie deficit and promote weight loss. The study also highlights the need for further research to understand the mechanisms behind energy compensation and its relationship with obesity.
