Men have to work harder than women to burn off their fat reserves, a new British study suggests.
During cycling tests at the University of Bath, 73 adults between the ages of 19 and 63 years, 32 of whom were women, had their fat oxidation levels measured.
Overall, the women tended to burn more fat when they exercised compared with men in a set time period, likely because they have a greater reliance on fat as a fuel source during exercise than men, the experts reveal.
Participants ranged from healthy to overweight and obese, suggesting this sex-based difference occurs regardless of body weight.
Females who are fit and healthy tend to burn more fat when they exercise than men, according to new research from a team of sports nutritionists at the University of Bath (stock image)
Study author Dr Javier T. Gonzalez and his colleagues included people with a wide range body mass indexes (BMIs) – from 18.6 to 32.9.
‘[Our sample] should be applicable to a large proportion of the general population,’ he told MailOnline.
‘Some were obese but no-one had any diagnosed metabolic condition like diabetes.’
The team tested the lifestyle and biological factors for optimal fat burning by asking participants to take part in a cycling fitness test and measuring key indicators, like ‘peak VO2’ – their highest possible oxygen uptake.
Their results, detailed in the International Journal of Sport Nutrition & Exercise Medicine, found that females and those who were physically fitter, right across the age ranges, burnt fat more efficiently.
How the body burns fat can make the difference between success and failure in endurance sport competitions, such as running or cycling.
The University of Bath team have published a second related paper in the journal Experimental Physiology this month.
For this study, researchers took fat and muscle biopsies from 36 healthy adult participants of both sexes to analyse how differences in the proteins in fat and muscle tissue might affect the ability to burn fat.
They found that the presence of proteins in muscle that are involved in breaking down stored fat into smaller fatty acids correlated with a greater ability to burn fat.
Proteins involved in transporting those fatty acids into the mitochondria of cells in muscle also consistently correlated with a greater ability to burn fat.
The molecular factors explored did not explain why females burned more fat than males, however.
Women displayed higher relative rates of fat oxidation than men, but this was unexplained by the proteins measured in this study, suggesting other factors determine sex‐differences in fat metabolism.
‘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,’ study author Ollie Chrzanowski-Smith.
Insulin sensitivity, which is is beneficial to the body, refers to how sensitive the body’s cells are in response to insulin.
High insulin sensitivity allows cells of the body to use blood glucose more effectively, reducing blood sugar. Low insulin sensitivity can lead to a variety of health problems like diabetes.
Researchers caution that the body’s ability to burn fat should not be equated with an ability to lose weight.
Losing weight is primarily produced by an energy deficit – when we consume fewer calories than we expend.
Researchers stress the importance of diet and exercise, particularly for overweight and obese individuals.
‘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,’ said Dr 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.’
