Читать книгу Why Men Don’t Iron: The New Reality of Gender Differences - Anne Moir - Страница 10

Scientists at the National Institutes for Health in Phoenix, Arizona, have discovered that, adjusting for differences in size, body composition and age, the resting male’s expenditure of energy is 5–10% greater than the resting female’s.¹³ Furthermore, since muscle is so much more metabolically active than fat, and men have more muscle, women more fat, the sex difference in body composition leads to even greater differences in resting expenditure of energy, favouring males. And not just while he is at rest; men generally expend more energy than women, even when they are engaged on identical tasks.¹⁴ His motor simply turns over at a higher speed than hers does, and the difference begins early in life. Researchers at the Dunn Nutrition Unit at Cambridge University found that even at 12 weeks old a sleeping male infant uses 12% more energy than a sleeping female infant.¹⁵

Typically, men are more active than women. In a study of some 2,000 adults in South Carolina (431 blacks and 1,574 whites) it was found that between the ages of 30 and 60 men were 43% more active than women.¹⁶ Higher levels of activity require more fuel, so his dietary needs are quantitatively greater than hers. If she eats too much the excess fuel will probably be stored as fat, while he has a greater chance of working it off.