By: Catherine Munaco
Owner, CoachMeFit West Bloomfield
A few months back, Robin, the mother of my old college roommate called me to ask me a few questions about diet and exercise for herself and her husband. “Mark and I are going to go on a diet!” She explained giddily. My response was less enthusiastic, but she assured me that Mark was a “meat and potato guy” who was “simply getting dragged along for the ride”. I had heard it before, but I gave her my advice on cardio routines and we were on our way.
Less than six weeks later, Robin called me in a fury to explain Mark’s “diet”. “He weighs himself in the morning,” she lamented, “and if he weighs more than he did the day before, he skips his morning muffin. If he weighs less, he eats his muffin.” She paused before exploding: “HE’S LOST 15 POUNDS! I’VE LOST ONE AND I NEVER EAT THE MUFFIN!”
If this were a rare occurrence, women wouldn’t have such a disdain for watching a male significant other drop 5 pounds in a week by eliminating his midnight snack. But instead, woman after woman has returned disgruntled after attempting to diet with her man.
So why is it so easy for men to drop weight compared to women? The easiest answer is the most annoying one: men’s body compositions are simply designed to burn more calories. Anthropologically speaking, men were the hunters and the protectors. Women had to bear children (which also means fatty breast and hip tissue). As we evolved, men continued to have more muscle mass than women in part because the males that survived had higher muscle masses and the strength to kill for food or protection, and the females that survived had the fat stores to carry healthy children to term. Because muscle is an active tissue, it burns more calories at rest than fat. Men have substantially more muscle than women, both because they have a lower percentage of body fat than women (A healthy level of 8-19% for males compared to 21-33% for women) and also more mass in general. In analyzing body fat, a body is generally divided into two groups: Fat mass percentage (FM) and fat free mass (FFM), which includes muscles, bones, and organs. If we compare two individuals with healthy body fat percentages (a 135 lb woman with a FM of 27% and a 165 lb male with a FM of 14%) the female would have a FFM of 98.55 pounds and the male would have a FFM of 141.9 lbs. That’s roughly 43 more pounds of active tissue for the male. It’s no wonder that skipping a morning muffin can still lead to weight loss when a man’s body will almost always have higher rate of calorie burn at rest (also called resting metabolic rate, or RMR). Whether it’s running outside or watching a movie, women simply do not burn as many calories as men.
To be fair, men have a similar frustration when they reach 30 and realize they can’t eat like they did in college. I call this the plight of the 30-year-old male. Part of this is because careers and families make it more difficult for a man to regularly exercise like he did in his college bachelorhood days. But even more significant is the fact that testosterone levels first start to drop at 30 in males. In some men, testosterone can drop by as much as 2% every year after 30. Among other things, testosterone is responsible for muscle development. (The significantly lower level of testosterone in females is another reason female muscle masses are lower than in males. Sigh.) After puberty and throughout the 20s, when testosterone levels are highest and males see their peak muscle mass, an average man can practically eat whatever he wants and not gain significant weight, as long as he remains relatively active. At this age, men are caloric vacuums. Their bodies can literally burn calories while they sleep. But when 30 hits and testosterone levels drop along with activity levels, men who are conscious of their weight often find themselves nibbling on carrots and whole bran cereal right along with the women in their lives.
The bottom line is that many factors contribute to muscle mass in both females and males. Muscle mass is directly linked to resting metabolic rate, or calories burned at rest. RMR is considered the baseline for measuring caloric expenditure. The intensity level of an activity can be measured by how much greater it is than RMR. If an activity burns twice as many calories than RMR, it is considered to be 2MR, if it burns 9 times more calories per minute, its considered 9MR, and so on. It makes sense, then, that a higher muscle mass leads to a higher RMR, and also a higher caloric expenditure in any activity. There’s not much a woman can do to increase her testosterone levels to those of a man, nor should she want to (a plethora of complications could arise). But women can still fight the weight loss battle more effectively by increasing their own muscle mass. And by staying away from diets with men and muffins.