Women who maintain high fitness levels burn more fat during exercise than men, according to groundbreaking research from sports nutrition experts at the University of Bath's Center for Nutrition, Exercise & Metabolism. These two new studies analyzed key factors influencing fat oxidation in endurance sports.
Understanding how the body mobilizes fat is crucial for metabolic health, insulin sensitivity, and reducing type 2 diabetes risk. In endurance events like running or cycling, efficient fat burning can determine victory or defeat.
Prior work by the same team revealed that endurance athletes deplete carbohydrate stores rapidly, making fat reserves vital for sustained performance.
The first study examined 73 healthy adults (ages 19-63; 41 men, 32 women) through cycling tests and core measurements. Results demonstrated that fitter participants across all ages—and women in particular—oxidized fat more effectively.
The second study delved into molecular mechanisms, analyzing muscle and fat biopsies. Proteins in muscle that break down stored fat into fatty acids and transport them to mitochondria (the cell's energy powerhouses) strongly predicted fat-burning capacity. However, these factors didn't fully explain women's advantage.
Lead author Ollie Chrzanowski-Smith, PhD candidate at the University of Bath, states: “Our study found that women tend to have a greater reliance on fat as a fuel source during exercise than men. Understanding the mechanisms behind these sex differences in fuel use may help explain why being a woman appears to provide a metabolic benefit for insulin sensitivity, an important marker of metabolic health.”
Enhanced fat oxidation may guard against future weight gain and support weight management. Yet, researchers stress it's distinct from weight loss, which requires a calorie deficit. For overweight individuals, combining diet and exercise remains key.
Dr. Javier Gonzalez from the University of Bath's Department of Health adds: “Weight management is mainly about energy balance, so to lose weight we need to eat fewer calories than we expend through our resting metabolism and physical activity. A higher ability to burn fat as fuel appears to be somewhat protected against future weight gain, which may be related to the influence of fat burning on food intake and energy expenditure.”
“Ultimately, a greater capacity to burn fat for fuel has potential benefits for endurance athletes by slowing the time point when they run out of precious carbohydrate stores.”
