But most guys? Almost the polar opposite. He seldom exercises, loves to drink beer and eat junk food, and doesn't seem to care as much about his weight. However, he loses weight easily on those few occasions when he actually adopts an exercise program or cuts back on calories.

Why, why, oh why do most men seem to lose weight so much easier than women?

Women Deposit Fat Differently Than Men

Men are apples and women are pears. Men tend to store fat in their abdomens, while women store it their legs, hips and butt. The way men store fat is dangerous because abdominal fat is linked with heart disease risk factors such as high blood pressure, high cholesterol, low HDL (good cholesterol), insulin resistance, type 2 diabetes and blood-clotting. The fat deposited on your legs and hips is survival fat. Women need fat to reproduce, and their genes are programmed to release this fat only as a last resort. Stress hormones such as norepinephrine stimulate lipolysis, which is the breakdown of fat into fatty acids. It works by triggering an enzyme that actually causes the release of fat— hormone-sensitive lipase (HSL). HSL activity determines your capacity to lose weight. HSL doesn’t work well when you’re overweight, particularly around your middle, but it becomes activated as you lose weight. The enzyme is activated better in women than in men, which is one reason why men have so much trouble getting rid of their “beer bellies.”

Women have a much lower risk of heart attack than men before age 55, but they tend to begin storing more fat in their abdomens as they approach menopause - heart attack rates at this point begin to equal those of men. The round little potbelly many 30-something-year-old women have is an indication of insulin resistance caused by lack of exercise and diets high in simple sugar and saturated fat. Younger women don’t have a lot of abdominal fat. If you do, it means you may have serious problems with your diet or exercise habits. If you have significant abdominal fat and are less than age 45, you probably need to make major lifestyle changes or you could be facing heart disease, stroke or cancer in the future.

Nervous System and Male Vs. Female Fat Loss

Women have the same problem activating fat in the lower body. While men have trouble getting rid of abdominal fat, women have a difficult time getting rid of thigh and butt fat. Scientists discovered that women lose fat in the upper body and face first and maintain lower body fat as long as possible. Studies have found that women who trained intensely with weights lost substantial fat from their arms and abdomen, but very little in their legs. One reason for this is the way the nervous system controls fat use in women.

Resting metabolic rate (RMR) is the main factor determining daily caloric expenditure and is critical for fat gains and losses. The nervous system sends a steady stream of impulses to the tissues that helps control metabolism and the rate at which you burn calories. This process works very much like the idle setting on a car— the higher the idle, the more gas the car uses. These nervous signals are lower in women, particularly as they age and don’t exercise.

It’s easier for men to lose fat than women because their nervous systems allow for release fats from the fat cells. Hormone-triggered fat release in the lower body is lower in women than in men, whereas fat release from the upper body depots is comparable. This means women can lose fat from the upper body easily, but have trouble doing so in the lower body.

Fat use at rest is higher in men than women, which is another reason why women have more trouble losing weight. After a meal, women store more fat just under the skin, while men store more fat around the internal organs in the abdomen.

Men Have More Muscle to Boost Metabolism

Muscle is one of the most metabolically active tissues in the body. The more muscle you have, the more calories you use. Muscle is also important for maintaining a high metabolic rate after the exercise is over. This extra post-exercise metabolism is an important way people lose weight. It may also help explain why it’s easier for men to lose weight than women. Less muscle mass in women means the resting metabolic rate in women is five to 10 percent lower than in men. Women store more fat than men. When metabolic rate is calculated relative to muscle (fat free mass), there is no difference in metabolic rate between men and women.

During exercise, women use more fat as fuel than men do. This would suggest that women could lose more body fat when they exercise. But they don’t; men burn more fat during recovery simply because they have more muscle mass, which makes up for women’s greater fat-using capacity during exercise.

Fat Loss and Exercise

These days, more women are starting exercise programs than men, but men still exercise more frequently and at higher intensity than women. Women are taking up exercise largely to lose weight. In several exercise and weight loss studies, men often lost weight while women didn’t. Body type may also help determine your capacity for weight loss. Women who have a lot of abdominal fat like men lose weight faster than women who carry fat in their hips, thighs and butt.

Food Intake

Women often underestimate their caloric intake. One study that measured caloric intake using a technique called doubly-labeled water showed that women typically underestimate their intake by 700 calories per day, while men underestimated their intake by 200 calories.

Women increase caloric intake when they go on an exercise program, while men don’t. This may be programmed in the genes: women need body fat to maintain healthy pregnancies. The increased caloric expenditure of exercise threatens body fat stores, which triggers fat control mechanisms to increase food intake. Men don’t need these controllers to the same extent as women.

Use Your Knowledge of Gender Differences To Boost Your Fat Burn

• Men have a greater nervous system response to exercise. Increase your nervous response by training more intensely. Include interval training in your fat loss exercise program. Intevals involve doing high- intensity exercise with rest intervals between repetitions. For example, on a running track, sprint the straightaways and walk the turns for two miles. In the gym, do 10-20 repetitions of one-minute sprints on the treadmill or elliptical trainer followed by one minute of rest between repetitions.

• Men have more muscle mass. Lifting weights will help you increase muscle mass and burn more calories. You will not gain the muscle mass of a man when you weight train, but you can increase it enough to boost your resting metabolism.

• Men don’t eat more food to compensate for the increased caloric cost of exercise. This is a tough one because you have to fight your genes. Drink more water and eat five or six small meals during the day that contain some protein. Dietary protein helps depress appetite.

• Men exercise more intensely. So don’t be a wimp. Make up your mind that you are going to train intensely for at least one hour several times a week.

Try these tips and you're metabolism will put a guy's to shame in no time.