A new study found that men who followed a low-calorie diet showed greater fat loss and improved blood sugar levels than women.
Edinburgh University scientists say estrogen — one of the main female sex hormones — makes it harder for women to lose weight by cutting calories.
This is likely due to the fact that estrogen promotes fat storage for fertility, as pregnancy requires a lot of energy. It appears that the male body is able to maintain a higher metabolic rate even if it has fewer calories, researchers report in the journal eLife.
Reducing calories while maintaining key nutrient levels has been linked to preventing conditions such as obesity, high blood pressure, and type 2 diabetes, as well as increasing life expectancy.
The research team studied the effects of a low-calorie diet on the health of mice and humans.
The six-week study included 96 rats whose daily caloric intake was 30% less than usual and 85 rats fed a normal diet.
The researchers found that a low-calorie diet lowered blood sugar levels by 22% in young men compared to 16% in young women.
The effect on body fat was even more striking: in men, fat mass decreased by almost 70%, while women did not lose fat at all.
The study found that female rats resisted fat loss because, compared to males, they broke down body fat less, expended less energy, and increased fat production after eating.
When the diet was started at an older age, there was no significant difference in fat loss between the sexes. The female mice lost about half of their body fat, about the same as the males.
A small weight loss study among 42 overweight or obese men and women confirmed that differences based on age and gender also occur in humans.
In the four weeks of the study, men under the age of 45 lost more than 16% of body fat, while women in the same age group lost only 8%, half of what men lost.
Men were limited to 2,000 calories per day and women to 1,500 calories, compared to the recommended intake of 2,500 calories for men and 2,000 calories for women.
There was no difference in fat loss between men and women over 45, as both sexes lost about 10% body fat.
The human study was not originally intended to test the effect of age and gender on diet, but the researchers were able to analyze the data retrospectively to resolve this issue.
Experts say a larger human study looking at the effects of age and gender is needed to confirm these findings.
Dr William Cawthorne, Senior Lecturer (Associate Professor) at the Center for Cardiovascular Sciences at the University of Edinburgh and lead researcher, explains: “Low-calorie diets have many health benefits and can promote healthy aging. Some previous research has shown that the effectiveness of these diets may differ between men and women, but our study is the first to show that these gender differences largely disappear when the diet is started at an older age. This could help us develop improved dietary strategies to prevent disease and promote healthy aging.”
Source: Medical Express
