If the effect was not as expected, you feel frustration. But even more frustrating is if you are following a diet with a man who has lost more weight than you.
The complaint is known: “He just needs to stop eating bread and he is already thin, but I…”.
Is it true that it is easier for men to lose weight than for women? And that, therefore, weight loss plans must be adapted depending on the gender?
The answers can be more complicated than it looks.
Full story
Last year, the University of Copenhagen, along with 8 other research institutions, started a study that put 2,500 pre-diabetic and overweight people on a strict calorie-control diet for 8 weeks.
The result? On average, men lost 11.8 kg, and women lost 10.2 kg.
Finally, there was evidence that men would find it easier to lose weight than women.
However, the statistics do not tell the full story.
Men have a greater energy deficit – Photo: Getty Images via BBC
“It was disappointing that the press focused on that difference without understanding math,” Professor Ian Macdonald of the University of Nottingham, who participated in the study, told the BBC.
Simply focusing on differences in the final weight was, according to him, “unfortunate”.
The reason is that all study participants received the same amount of food (810 calories), regardless of the fact that men had a greater energy deficit.
First, men were bigger (they weighed 109 kg on average, compared to women 96 kg) and therefore had more weight to lose.
Therefore, the difference in the result “was only a consequence of the difference in body size. If we had smaller men and bigger women, it would be the other way around ”, explains the professor.
This was not an oversight on the part of scientists.
In the survey, if women were heavier than men at the beginning of the diet, the result would have been the opposite. – Photo: Getty Images via BBC
The eight-week plan was not the main focus of the research, but the start of another three-year study.
“Participants had to lose 8% of their body weight in that 8 week period to be recruited on a random diet and exercise maintenance period for the next 3 years, as part of a diabetes prevention study,” says Macdonald.
There were also reports that men lost weight “better” than women: blood pressure and heart rate decreased further and there were differences in the level of cholesterol drop.
But Macdonald clarifies: “Although there were some statistical differences, in terms of clinical relevance, they were not significant. Men and women have experienced weight loss benefits ”.
So there is no difference?
The professor admits, however, that there are differences in weight loss between men and women.
“For the same body mass index, men tend to have more fat-free mass (muscle) and less fat mass. This is due to the effect of sex hormones on body fat mass, as well as fat distribution. ”
Therefore, “women generally find it a little harder to lose weight,” according to Tom Little, nutritionist and founder of Color-Fit, a company specializing in diets for professional athletes.
“Men have more testosterone and are genetically designed to have a higher percentage of muscle and less fat. Muscle mass has a higher metabolism than fat, so the more muscle you have, the more calories you can burn, even when you don’t exercise, ”he says.
“However, most studies show that, although men initially lose weight more quickly, the differences are made up over time.”
Are there more suitable diets for men or women?
This year, new research from the University of Iowa examined whether men are more likely than women to succeed on the ketogenic diet – a low-carb, high-fat diet plan. The research is so new that it has not yet been officially published: “Until now, we have presented it only at scientific meetings”, explains principal researcher E. Dale Abel.
The study was carried out “by chance”. The researchers were investigating the impact of the ketogenic diet as a treatment for heart failure. They noticed that the male rats on the diet lost weight, but the females did.
“We realized that this difference was significant between males and females in the ketogenic diet. We thought ‘wow, how drastic!’. So the next question was whether it was reproducible, ”explains Jesse Cochran, the research coordinator.
“Every time, it was the same thing: male rats lost weight, females gained.”
Among rats, females gained weight and males lost weight. – Photo: Getty Images via BBC
To find out if the differences were due to sex hormones, they studied females who had their ovaries removed to simulate a postmenopausal state. They found that, although they gained weight (due to estrogen deficiency, normally produced by the ovaries), the keto diet did not intensify this tendency.
Alert!
Nevertheless, university scientists warn that, first of all, although the mice have lost muscle and fat, this may be because the rat version of this diet is restricted in protein (which is necessary for the mice on this diet to produce the substances needed to convert glucose into energy).
The ketogenic diet for humans contains proteins, so there may be no muscle loss.
Abel and the team have already received media attention about the study, after presenting it at scientific meetings.
“I received a lot of reports from women or their health professionals who said, ‘It makes sense, I always wondered why (it didn’t work for me),’” he says.
“However, I want to warn you, in capital letters, that a mouse is not a person. They can give us an idea, and we are certainly exploring molecular issues and other hormones that can help us understand the difference between men and women, ”he said.
“What is fundamental is that, if tests on humans are carried out, careful research must be done to determine if there are differences in the effect of these diets due to gender,” he adds.
One reason we still don’t have a clear answer as to whether some diets are more suitable for each gender is that science in general has been adapted to just one of them.
“In medicine, in general, much of what we do in practice is based on studies of men. There is a growing awareness that this is why I think that an observation like Jesse made is crucial, as it highlights that there are fundamental differences in biology “, explains Abel.
Should you choose a gender-based diet?
The answer is: No. At least until there is more research that clarifies things well.
The expert warns: ‘a mouse is not a person’. – Photo: Getty Images via BBC
However, Rick Miller, a nutritionist at King Edward VII Hospital in London, explains that there are some considerations you can keep in mind.
“Gender-based plans can offer some customization in terms of exercise options or variations that best suit men or women. But in terms of nutrition, the general requirements for proteins, carbohydrates and fats are based on body composition (proportions of fat and lean mass). Therefore, a man and woman of the same proportions will have similar needs for calories and nutrients per day. ”
“When it comes to micronutrients (vitamins and minerals), there are some differences between men and women. For example, menstruation increases a woman’s iron needs due to blood loss. ”
The key to the success of any nutrition plan, according to him, “is the personalization of lifestyle, medical history and goals”.
Recommendations
Although we don’t (yet) have definitive answers to the questions, the experts we talked to have some advice for dieters, regardless of gender.
Everyone agrees that instead of adopting a very restrictive diet, it is better to opt for the “slow and steady” approach: making changes in healthy eating that are sustainable in the long run.
“Ask yourself, ‘Can I maintain this change for life?’ If the answer is ‘no’, it is possible that you could be a little more flexible and see what else you could change. This prevents you from making drastic decisions that you couldn’t keep. ”
The idea, says Millar, is that “don’t feel like you’re on a ‘diet’, but that you’re just making small changes.”