01 February 2012

Why do men lose weight faster?

You're both on exactly the same diet and you both exercise. But he loses weight faster than you do. Time to take revenge? Or time to find out exactly how his body does this?


You're both on exactly the same diet and you both exercise. But he loses weight faster than you do. Time to take revenge? Or time to find out exactly how his body does this?

Let's have a look at some of the most important factors that determine body weight to see whether this is true, or not.

Resting energy expenditure

Resting energy expenditure (REE) is defined as the amount of energy required to support normal body functions and to maintain the energy balance of the body (homeostasis). REE supports body functions such as breathing, the circulation of the blood, energy used by the nervous system and keeping our body temperatures constant (Krause, 2000).

The most important factors that determine REE are body size and composition.

Generally speaking, men are bigger than women. This means that they would require more energy to maintain REE. In addition, men tend to have a higher percentage of lean muscle tissue than women, so the metabolic dice are loaded against women when it comes to REE.

Because of their bigger bodies and higher percentage of lean muscle mass, men will have a higher REE and thus be less likely to gain weight.

Body fat percentage

Women have a higher proportion of body fat than men. This is a genetic adaptation which ensures that the female body is cushioned to bear children. The higher body fat percentage in women lowers their metabolic rates by 5 to 10% compared to men (Krause, 2000).

Thus, women need less energy to sustain their normal metabolism and will be more inclined to gain weight if their food intake exceeds their energy requirement.

According to Prof Tim Noakes, one of South Africa's leading experts in the field of exercise physiology, even women who are elite athletes have a higher body fat percentage than their male counterparts.

Average men and women have body fat percentages of 14% and 24% respectively. Elite male and female distance runners, with the same body mass or weight, have body fat percentages of 5% and 10% respectively (Noakes, 1991).

If even our top female athletes have double the amount of fat in their bodies than their male counterparts, then ordinary women will generally carry more fat than ordinary men. Consequently, females also have a lower percentage of lean body or muscle mass when compared to men.

Prof Noakes points out that on average female runners have 14% less lean muscle mass than male runners of the same weight.

With more body fat and less lean muscle tissue, females are thus less likely to be lean and mean and it will also take much more effort to reduce body mass and body fat percentage in women than in men.

Lower VO2 max

Another factor that can hamper weight loss in women is the fact that they tend to have a lower VO2 max. The VO2 max is a measure used in exercise physiology to describe the maximum amount of oxygen an athlete can take up to use for exercise.

Unfortunately, female athletes have a lower VO2 max compared to male athletes of the same weight (Noakes, 1991). Consequently, women who use exercise to promote weight loss will not be able to exercise at the same level as men, and will therefore, burn less energy in a standard exercise session.

The unfair advantage

It is evident that men have a number of unfair advantages over women when it comes to losing weight. Most couples have experienced this when both partners go on a slimming diet and do exercise to lose weight: the husband loses more weight at a faster rate than the wife.

So, the female of the species has to work so much harder and stick to her diet for so much longer and do so much more exercise to achieve the same results as her male counterpart. This seems unfair, but it is a fact and there is nothing we, as females, can actually do about this – except to persevere, of course.

Women do need to eat less for longer and exercise harder to lose the same amount of weight as their partners.

Saving grace

The saving grace that counts in favour of women is that the female sex is much more motivated to lose weight and, in most cases, less susceptible to temptations when it comes to cheating. Female dieters won't as easily succumb to a night out with the boys, which entails consuming copious amounts of beer and fatty snacks.

This may not seem much of a compensation to most women who struggle to lose weight, but if we keep in mind that “the hand that rocks the cradle, controls the world”, then women can exercise iron control and achieve their goals of weight loss despite the unfair advantage that men enjoy.

- (Dr Ingrid van Heerden, updated by Health24, January 2012)

(Pic: iStock)

(Noakes, T (1991). Lore of Running. Oxford University Press, Cape Town; Krause (2000). Food, Nutrition & Diet Therapy. 10th Edition. Mahan LK & Escott-Stump, S Editors. WB Saunders Co, Philadelphia.)

Any questions? Ask DietDoc

Read more:
A look at male weight gain 
Keep going when you're plateau-ing


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