Why are Americans burning more calories than ever but still gaining weight? Study reveals reason behind obesity crisis

Research indicates that while wealthier populations burn more calories, their diet, particularly high in ultra-processed foods, contributes to obesity.

Despite exercising regularly and burning more calories than ever, people in wealthier countries are struggling with rising obesity rates. It's a confusing paradox: how can populations that move more and burn more energy continue to gain weight? The answer may not lie in physical activity, but in what's on our plates.

Study reveals that people in wealthier nations burn 6% more calories but consume more ultra-processed foods, leading to obesity.

Developed nations burn more calories but still gain weight

A March 31 Duke University study challenges the long-held belief that inactivity is the main cause of obesity. By comparing over 4,200 people across 34 populations, from Tanzanian hunter-gatherers to Norwegian office workers, researchers discovered that people in developed nations actually burn more calories daily than those in traditional societies. Yet, they carry significantly more body fat.

Wealthier nations burn more calories but face rising obesity due to diet choices. (Shutterstock)

Published in Proceedings of the National Academy of Sciences, the study used the advanced ‘doubly labelled water’ method to measure real-world energy expenditure. Even after adjusting for body size, people in wealthier nations burned about 6 percent more calories. Surprisingly, their physical activity levels were similar to those of people in developing nations.

Why is diet more important than exercise in the obesity crisis

So why the weight gain? The key factor isn't movement, but diet. In populations where dietary data were available, researchers found a clear link between higher consumption of ultra-processed foods, like sugary drinks, packaged snacks, and ready meals and higher body fat. These foods are easier to digest, meaning the body absorbs more calories, and they may disrupt hunger signals, leading to overeating.

While people in wealthier nations are burning more calories, they're also eating more, particularly ultra-processed foods that promote fat storage. The result? Bigger waistlines, despite similar activity levels.

The study highlights that tackling obesity requires focusing on food quality, not just promoting exercise. Researchers concluded that the rise in obesity is driven mainly by what people eat, not how much they move. For long-term solutions, improving the food environment, making healthy, minimally processed options more accessible, may be more effective than simply urging people to "eat less, move more."

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.