Females who are physically fit tend to burn more fat when they exercise compared to men, according to new research by sports nutritionists at the University of Bath.
In two studies, the experts have investigated the factors that most influence an individual’s capacity to burn body fat when engaging in endurance sports.
The team previously demonstrated that the body’s carbohydrate stores deplenish quickly among endurance athletes competing in distance events. This means that tapping into the body’s fat reserves becomes essential to an athletes’ ability to perform.
The first study was designed to investigate the lifestyle and biological factors for optimal fat burning. The participants – 73 healthy men and women – took a cycling fitness test as the researchers measured key indicators.
The trial revealed that females, as well as those who were the most physically fit, burned fat more efficiently when exercising regardless of age.
In a second study, the researchers set out to determine which molecular factors in muscles and fat tissue control how fat is burned. The experts biopsied fat and muscle tissue from participants to analyze how differences in the proteins may affect the ability to burn fat.
The results showed that the proteins in muscle that are involved in breaking down stored fat into the smaller fatty acids, and proteins involved in transporting those fatty acids into the mitochondria in muscle, consistently correlated with a greater ability to burn fat. The findings could not explain why this process is more efficient among females.
“Our study found that females typically have a greater reliance upon fat as a fuel source during exercise than males,” said Ollie Chrzanowski-Smith, the lead author of both studies.
“Understanding the mechanisms behind these sex differences in fuel use may help explain why being female seems to confer a metabolic advantage for insulin sensitivity, an important marker of metabolic health.”
According to the researchers, the ability to burn fat as a fuel appears to protect against future weight gain, ensuring good weight management. On the other hand, they caution that the body’s ability to burn fat should not be equated with an ability to lose weight. When it comes to weight loss, especially for overweight individuals, the study authors stress the importance of diet and exercise.
“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,” explained Dr. Javier Gonzalez.
“However, people with a higher ability to burn fat as a fuel seem to be somewhat protected against future weight gain, which might be related to how fat burning affects food intake and energy expenditure.”
“Ultimately, a greater capacity to burn fat as a fuel has potential benefits for endurance athletes, by delaying the timepoint when they run out of precious carbohydrate stores.”
The study is published in the International Journal of Sport Nutrition and Exercise Metabolism.
By Chrissy Sexton, Earth.com Staff Writer