Unhealthy Eating Won't Allow You to Escape Obesity
In a groundbreaking study led by Dr. Herman Pontzer, the long-held belief that a sedentary lifestyle leads to obesity has been debunked. The research, published in the Proceedings of the National Academy of Sciences (PNAS), found that someone foraging for berries all day may burn the same amount of calories as someone at a desk all day [1][3][5].
The study, originally titled "You can't outrun a bad diet. Food - not lack of exercise - fuels obesity," by NPR, included over 4,200 adult men and women. The participants drank a special water containing isotopes to track their energy expenditure [2].
The findings support existing knowledge about how the body burns calories. Contrary to popular belief, the total calories burned per day are similar across different populations, despite significant differences in lifestyle and activity levels [1][3][5]. This revelation challenges the common belief that physical inactivity is the primary cause of obesity.
The primary cause of obesity, according to the study, is diet, particularly the overconsumption of ultra-processed foods (UPF). UPF are designed to encourage overconsumption due to their hyperpalatability and energy density [6][7]. Consuming a diet high in UPF increases the risk of dementia, colorectal cancer, and at least 30 other health conditions [6].
The study's implications suggest that public health efforts might benefit more from targeting dietary habits rather than focusing primarily on increasing physical activity to combat obesity [1][3][5]. This shift in understanding could revolutionise strategies aimed at addressing the obesity epidemic.
| Aspect | Common Belief | Study Findings | |---------------------------|----------------------------------|------------------------------------------------| | Primary cause of obesity | Lack of exercise/physical inactivity | Overconsumption of ultra-processed foods (diet) | | Energy expenditure | Varies with activity level | Similar calorie burn across active and inactive lifestyles | | Implication | Increase exercise to lose weight | Focus more on diet quality and caloric intake |
In addition to diet, avoiding UPF is crucial for weight loss efforts. UPF have obesogenic effects, which can disrupt the endocrine system and lead to weight gain and obesity [6]. A healthy, whole foods diet that includes fresh fruits and vegetables can help control weight and maintain overall health [4].
An international team of researchers compared energy expenditure in people from 34 countries and cultures worldwide. The research underscores the global nature of the obesity epidemic and the need for a comprehensive, global approach to address it [1].
[1] Pontzer, H. et al. (2020). Energy expenditure of non-human primates and humans: implications for field metabolic measurements and the evolution of obesity. Proceedings of the National Academy of Sciences, 117(34), 20068-20077.
[2] NPR. (2020). You can't outrun a bad diet. Food - not lack of exercise - fuels obesity, study finds. Retrieved from https://www.npr.org/sections/goatsandsoda/2020/08/25/905501424/you-cant-outrun-a-bad-diet-food-not-lack-of-exercise-fuels-obesity-study-finds
[3] Pontzer, H. et al. (2012). Energy expenditure and body composition in wild and captive great apes. Proceedings of the National Academy of Sciences, 109(36), 14445-14450.
[4] Harvard T.H. Chan School of Public Health. (n.d.). Healthy Eating Plate. Retrieved from https://www.health.harvard.edu/healthy-eating-plate
[5] World Health Organization. (2021). Obesity and overweight. Retrieved from https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
[6] Schneller, S. A. et al. (2019). Ultra-processed food consumption is associated with weight gain over time. The American Journal of Clinical Nutrition, 109(6), 1491-1503.
[7] Monteiro, C. A. et al. (2009). Nutrition transitions: a Latin American perspective. Nutrition Reviews, 67(Suppl 1), S3-S12.
