Probably the first thing that comes to most people’s mind when it comes to losing weight is calories. You’re always hearing about counting calories when the talk revolves around diets, but what’s the use in counting them if you don’t know how many calories you need per day to lose weight.

The number of calories you need is going to depend on one main thing; how many you’re burning every day. That, in turn, is governed by your basal metabolic rate and your activity level. That means the amount of calories your need each day will be determined by your goals, your activity level and your metabolism. If you’re looking to lose weight (fat), you’ll obviously have lower calorie requirements than if you’re trying to gain mass. The same is true if you are extremely active vs. sitting around in your cubicle of despair all day long. Higher activity levels require more calories to sustain than do lower ones.

How can you determine what your daily calorie needs are?

Average daily calorie requirements have often been quoted as 2,000 calories a day for women and 2,500 for men. The problem with that is that virtually no one fits the mold of “average”. The average figure fails to account for differences in metabolism, activity levels, and goals. So, how can you determine yours?

One way is to use the Harris-Benedict equation to derive your basal metabolic rate and then add appropriately to take into account your activity level. The H-B equation is different for men and women.

Men’s Harris-Benedict formula:
66 + (13.7 x weight in kg) + (5 x height in centimeters) – (6.8 x age)

Women’s Harris-Benedict formula:
665 + (9.6 x weight in kg) + (1.8 x height in centimeters) – (4.7 x age)

One problem with the Harris-Benedict formula is that it fails to account for individuals with high levels of lean body mass, such as athletes or bodybuilders. According to research done in the late 1980’s and early 1990’s, each pound of lean body mass needs approximately 16 calories per day to sustain itself.

That provides a better way to calculate your daily calorie needs if you’re exceptional in the LBM department. For example, a 200lb man with 12% bodyfat has 176lbs of lean body mass. That means that in order to sustain it he’ll need an average of 2,816 calories per day. Note that if you’re the aforementioned cubicle dweller that watches sports, rather than participates in them, you’ll need only this much. If you have high activity levels, you’ll need more calories to compensate.

Activity compensation factors:
Light exercise / activity a couple of days a week = 1.2
Moderate exercise / activity, 4 of days a week = 1.5
High levels of activity and sports 6 or 7 days a week = 1.7

Multiply the number you obtained from your lean body calculation by these correction factors to obtain your average daily calorie needs.

Have a great weekend, and keep losing your fat!