First, let’s talk about what a calorie is. According to about.com the official definition of a calorie is “…the amount of heat needed to raise the temperature of a liter of water 1 degree (DHHS).”  Ok, now what does that really mean to us. A calorie measures the energy in food and beverages we take in and we need energy for everything we do in our daily lives. That said, calories are a necessary evil. You can’t survive without them, but too many can make you overweight and in some cases even obese. But it’s very tricky figuring out how many you need.

There are a lot of factors to take into account when figuring out how many calories you need. are you trying to lose weight, and how much weight are you looking to lose a week.

About.com has a step by step way to calculate your needed calories.  Step one is to calculate your BMR with the following formula:
Women:
655 + (4.3 x weight in pounds) + (4.7 x height in inches) – (4.7 x age in years)
Men:
66 + (6.3 x weight in pounds) + (12.9 x height in inches) – (6.8 x age in years)

Calculate Activity:
Step two: In order to incorporate activity into your daily caloric needs, do the following calculation:

    • If you are sedentary : BMR x 20 percent
    • If you are lightly active: BMR x 30 percent
    • If you are moderately active (You exercise most days a week.): BMR x 40 percent
    • If you are very active (You exercise intensely on a daily basis or for prolonged periods.): BMR x 50 percent
    • If you are extra active (You do hard labor or are in athletic training.): BMR x 60 percent

Add this number to your BMR.

The result of this formula will be the number of calories you can eat every day and maintain your current weight. In order to lose weight, you’ll need to take in fewer calories than this result. Based on myfitnesspal, if you want to lose 1 lb a week you need to have a calorie deficit of 500 calories. So if your calorie needs are 1800 calories per day, you would want to only take in 1300 calories per day.  So then you’d want to eat very little calories if you want to lose weight, right? Not true. If you eat too little calories, you will put your body into starvation mode, and that isn’t good. Your body will store fat, and then you won’t lose weight either. According to livestrong.com, the recommended minimum caloric intake one should have is 1200 calories a day for women, and 1500 calories a day for men.

Of course, athletes will need more calories then the average person. On the livestrong website, it says that male athletes should consume about 23 calories per 1 lb. of body weight, while female athletes need about 20 calories per 1 lb. A 165-lb. male athlete would need about 3,795 calories a day, while a female of the same weight would need 3,300.

I’ve only touched the surface on the calculations of caloric intake. There is so much to consider and it’s good to use a site such as myfitnesspal to figure out how many calories you are taking in a day compared to how many your body actually needs.