Metabolic Rate - Why it's Harder for Women to Lose Weight
Yuri Elkaim, BPHE, CK, RHN
It has been my experience that, in general, women are at a distinct disadvantage when compared to men when it comes to obesity and their ability to lose weight.
First, women generally have smaller body sizes, and, as a result, their energy expenditures have been shown to be less than that of men performing the same activities.
For example, according the American College of Sports Medicine, an 85-kg male running 10 kilometers in 45 minutes would expend 917 calories. However, A 55-kg female running the same distance in the same time would expend only 593 calories!
The lower energy output is primarily due to the fact that women have a smaller body mass than men.
Women are also at a disadvantage because they tend to have less fat-free mass than men. Since fat-free mass (or muscle mass) is responsible for fueling our metabolism, the average daily metabolic rates (ADMR) for women will therefore be less than that of men of the same ages and body sizes.
The average basal metabolic rate (BMR) for men is considered to be 38 kcal/m2/h while it is only 35 kcal/m2/h for women. BMR is the minimum number of calories your body needs to sustain life in a resting state.
It can be looked at as being the amount of energy (measured in calories) expended by the body to remain in bed asleep all day! Amazingly, your BMR can be responsible for burning up to 70% of your total calories on a daily basis, but this figure varies due to different factors such as lean body mass, gender, age, genetics, and your activity level.
Your BMR is the largest factor in determining overall metabolic rate and how many calories you need to maintain, lose or gain weight.
According to exercise physiologists William McArdle and Frank Katch, the average maintenance level (BMR) for women in the United States is 2000-2100 calories per day and the average for men is 2700-2900 calories per day.
Since men have a higher BMR than women, therefore, they will in turn have a higher ADMR (average daily metabolic rate). The fact that women are in many cases smaller than men and that their ADMRs tend to be lower than that of men makes the weight loss process more difficult for women than for men.
The differences between men and women such as increased muscle mass and BMR are mainly hormonally caused. Prior to puberty, men and women are physiologically similar; it is the presence of either testosterone or estrogen that leads to physiological changes. Increased testosterone leads to an increase in muscle mass whereas estrogen leads to an increase in fat deposits. With exercise, women increase their levels of testosterone, thereby increasing their muscle mass and BMR.
Here’s a simple formula you can use to figure out your basal metabolic rate. It’s known as “Katch-McArdle formula” and it’s a helpful tool because it calculates BMR based on lean body weight (it’s more accurate than other formulas that simply look at body weight).
If you have had your body composition tested and you know your lean body mass, then you can get the most accurate BMR estimate of all. This formula takes into account lean mass and therefore is more accurate than a formula based on total body weight. Since this formula accounts for lean body mass (LBM), this single formula applies equally to both men and women.
BMR (men and women) = 370 + (21.6 X lean mass in kg)
Now that you know your BMR would you like to know how many calories you’re “actually” burning on a daily basis? This is referred to as your Total Daily Energy Expenditure (TDEE).
To determine your TDEE from BMR, you simply multiply your BMR by the following activity multiplier that most suits you:
It has to be said that I’m not huge fan of counting calories so if you want to lose weight without tediously counting calories then here are few things you can do to increase your basal metabolic rate to allow your body to burn more fat even while you’re asleep!
1. Resistance train – a minimum of 3 times per week is recommended. Use your body weight or dumbbells but make sure it gets done.
2. Interval cardio train – studies have shown that high-intensity cardio can raise your metabolic rate for up to 24 hours post-exercise. Interval training allows you to work at a greater intensity while saving you tremendous amounts of time versus low-intensity, long, boring cardio.
3. Drink 2-3 cups of green tea each day – green tea has been shown to increase BMR by increasing your body’s temperature. It is a safe thermogenic aid that also contains tremendous amounts of antioxidants.
4. Eat more raw foods – raw living foods are rich in enzymes. These enzymes are essential for every single metabolic reaction in your body. The more enzymes you can acquire from food, the less stress you impose on your digestive system, the more energy you’ll feel, and the more you increase your metabolic fat-burning engine!
American College of Sports Medicine. (1995). ACSM’s guidelines for exercise testing and prescription (5th ed. pp. 53-54, 62-64). Baltimore: Williams & Wilkins.
McArdle, W. D., Katch, F. I., & Katch, V. L. (1996). Exercise physiology: Energy, nutrition, and human performance (4th ed.; pp. 151-152, 408-411, 541-542). Baltimore: Williams & Wilkins.
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