New research published in the Proceedings of the National Academy of Sciences has shown that caloric intake is the main driver of obesity worldwide rather than sedentary time.
The study included over 4,000 adults from across the world who had a wide range of lifestyles and economic statuses. The distinct populations in the study included hunter-gatherers, pastoralists, farmers, and industrialized populations. For all participants, energy expenditure was measured along with two measures of obesity, body mass index (BMI) and body fat percentage. Additionally, economic development was noted for all participants. Economic development has been associated with increased obesity and health issues around the world, and this study sought to determine whether increased obesity is more related to increased caloric intake or the more sedentary lifestyle that tends to come with greater economic development.
The results of the study showed that, as expected, greater economic development was related to greater rates of obesity both in terms of BMI and body fat percentage. However, people in wealthier countries also expended just as much energy per day, and sometimes even more energy per day, than those in less developed countries. Energy intake via diet was greater in more economically developed populations, suggesting that diet plays a major role in the higher obesity rates in these countries. Additionally, the percentage of ultra-processed foods in one’s diet was associated with body fat percentage. Together, these results suggest that dietary intake plays a much greater role than energy expenditure in obesity.
The authors noted that the root causes of obesity in developed countries have been unclear for decades. However, the results of this study clearly point to diet, rather than a lack of physical activity, as the main cause of obesity in highly developed countries such as the U.S. In the future, public health efforts to curb obesity may promote diet and exercise as important but not interchangeable factors when trying to lose weight.
Sources: Proceedings of the National Academy of Sciences, Science Daily
