What is a calorie?

A unit of measure that tells you how much "energy" is in a type of food. Carbohydrates and protein have 4 calories per gram while fat has 9 calories per gram. Some diets also consider the glycemic index of foods, or how fast a food increases the level of glucose in the blood.

How many calories do people need in a day?

Depending on who you talk to or what you read, the number of calories you need depends on things like your current weight, height, age, level of activity, metabolism rate, and usually another set of (seemingly) random numbers. A very rough rule is to multiply your weight in pounds by 12 - this is probably the minimum calories you need to get by day to day; as an athlete, you will need more - you could burn an extra 800 (or more) calories every hour during a workout. If you want to continue to be able to practice, you need to replace this spent energy. How? By eating!!

Basic guidelines state that in a general diet, approximately 60 % of your daily calories should come from carbohydrates, 15% from protein, and 25% from fats. This will vary from plan to plan and from person to person, and the exact breakdown is up to you.

Remember, you should consult your physician before beginning any type of specific diet to avoid or reduce the chance of medical complications. Most experts also advise athletes to break up their meals into smaller mini-meals throughout the day, as opposed to just a breakfast, lunch and dinner.

Looking around on the web, I’ve seen a number of calculations which allow me to figure out exactly how many calories I need to maintain, gain, or lose weight. Here are some of them:

(Note that for all of these I’ll be using my own stats: I do light activity, walking 3 times per week, about 3 miles per day. Some weeks i do more, but recently this has been the pattern. I’m currently at 271.4 lbs (or 123.104 kg), 6′1 ft (or about 1.83m), and 28 years old. Oh, and male. Can’t forget that part. And since some of the numbers I’ll be running are in pounds, you folks using the metric system can use this handy converter.)

Calculation 1

1. First, calculate your base metabolic rate (BMR), or how many calories you burn by simply existing, though hopefully you’re doing more than just laying in bed and watching daytime television, and therefore simply “existing.” (Unless you’re in the hospital getting better, then in which case, for the love of God, stay in bed watching daytime television so you can continue existing, at least corporeally. And better yet, instead of watching TV, read. Like you’re doing now.)
   • If you’re female:
     BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
   • If you’re male:
     BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in years)

   For me, this would be the following: BMR = 66 + (6.23 x 271.4) + (12.7 x 73) - (6.8 x 28) = 2865.45.

   (I know this seems like a lot, but… well, frankly, this isn’t the only one, and it’s the most conservative equation I’ve yet found.)

2. Second, calculate your daily activity. If you exercise above and beyond simply walking to your car or through the grocery store, then this is where you put it. (Of course, if you walk miles to your car or spend hours scooting up and down the isles at the grocery stores, then by all means count that as exercise, I guess. In fact, forget I said anything about cars or stores.)
   • If you get little or no exercise (leading a sedentary lifestyle), take your calculated BMR and multiply it by 1.2.
   • If you get some exercise (light exercise 1 to 3 times per week), take your calculated BMR and multiply it by 1.375.
   • If you get a moderate amount of exercise (exercise 3 to 5 times per week and do the equivalent of 20 miles weekly, walking 3-4 miles per hour), take your calculated BMR and multiply it by 1.55.
   • If you’re into hard exercise (very active, and working out 5 or more times per week, full workouts), take your calculated BMR and multiply it by 1.725.
   • If you’re a mountain climber, lumberjack or polar explorer (or anything that would be defined as “extra active”, meaning very hard exercise and a physical job or rigorous training), take your calculated BMR and multiply it by 1.9.

   (To see how different activities compare to others as far as burning calories is concerned, check out this article from the Harvard Medical School.

   In my case, I’m in the light exercise category, though I sometimes go to the moderate exercise category, and sometimes, rarely, I’m totally lazy. (I haven’t done hard exercise in a few months.) Using my previous BMR, for light exercise, I need 2865.45 x 1.375, or 3939 calories per day if I don’t wish to lose or gain weight. If I’m not exercising (and not laying in a hospital bed, then I need 2865.45 x 1.2, or 3438.54 calories per day if I don’t wish to lose or gain weight. At least, according to this formula, though it seems kind of high to me. Of course, being at 271.4 lbs, if I don’t do any exercise, then I’ll probably end up with diabetes. Needless to say, this is less than desired.

   So, if I wanted to lose weight, I should probably either eat 500 calories less per day than the required for my daily activity, exercise a lot more, or do a combination of the two, by eating less and exercising. (I’ve been taking that last approach recently, and have lost about a pound a week since January 1 of this year. I started the year at about 276.5. I can’t say it’s even felt like trying, really. When I want to feel “full”, I stuff myself full of salad, and always make my own mostly-vinegar based dressings. I also don’t really drink sodas, don’t eat fatty meats, don’t eat pasta or too much bread, and my only real big sinful pleasure is a Starbucks Frappuccino. A few times a week. Though I make it a point to exercise some more on the days I do have one.)