A recent study published in 2025 has found that increased calorie intake plays a much larger role in obesity than physical inactivity, particularly in economically developed countries. Researchers emphasize that diet, especially the consumption of ultra-processed foods, is the primary driver of overweight and obesity, overshadowing the impact of lack of exercise by about tenfold. The study highlights that reducing intake of processed foods may be key to addressing rising obesity rates. This challenges the common belief that sedentary lifestyles are the main cause of obesity. The research also provides insights into the limitations of exercise alone in preventing and treating obesity and suggests that dietary changes offer the most effective long-term solutions. Additionally, related reviews in scientific journals have examined the biological mechanisms linking ultra-processed foods to obesity and discussed implications for policymakers.