Why don't guys get thunder thighs?

Philip J. Goscienski, M.D.

January 2006

Women have a harder time losing fat than men do and the hardest of all to lose is thigh fat. This isn't perversity but protection; not nature's whimsy but wisdom. Thunder thighs is an embarrassing term but women should take at least a little comfort - I know, it's easy for a guy to say - from the fact that nature intended it that way.

A couple of million years of evolution produced humans with traits that developed to ensure the survival of the species. A few extra pounds of fat helped humans to make it through periods of food scarcity. We should note here that scarcity does not mean famine, which was rare during the Stone Age. In those parts of Africa where humankind arose the temperate climate provided hundreds of plant species, some of which would survive under even the most severe climate conditions.

The typical pear shape of a woman and the apple shape of a man didn't evolve by chance. If prehistoric men had fat thighs they couldn't run as fast. If a woman had to carry extra fat in the abdomen it might crowd the uterus late in pregnancy.

The story of fat goes beyond the fact that it accumulates in a different pattern in women than it does in men. It behaves differently too. A man's abdominal fat is known as hunter's fat, a storehouse of portable energy that evolved long before backpacks did and was available for days at a time during a prolonged hunt. The thigh fat of a woman is a precious asset that nature provides to yield long-term energy - enough to sustain her and the infant she carries within or at the breast. That's why thigh fat gives up its energy so grudgingly. It may have to last for weeks, not just days.

Not only is body fat essential to healthy pregnancy and breastfeeding, it plays a role in ovulation. When a woman's body fat drops below a certain percentage of body weight the ovaries stop releasing eggs and menses cease. There's no point in reproducing if there won't be enough stored energy to support the mother and infant. Body fat levels also determine when a young girl begins to ovulate. Nature seems to know when a woman's body has enough fat on hand to carry a pregnancy to term. Since childhood obesity is increasing, it shouldn't surprise us that the average age at which young girls become capable of pregnancy is falling. In the early 19th century the average age at menarche (the age at which menses begin) was 16 years. At the end of the 20th century it had fallen to 12 years.

These primitive patterns are meaningless in a society in which obesity begins in infancy and lasts a lifetime, where one person in 20 is a hundred pounds or more overweight and where two thirds of individuals are overweight but undernourished. The Big Apple no longer stands for New York City but for the average American, male and female, whose expanding waistline is an outward sign of internal danger. The incidence of coronary heart disease and type 2 diabetes increases with every inch of girth.

Nature rarely makes mistakes. Your fat serves a purpose. Take a few steps - literally - to make it a blessing, not a burden.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.