This is an often misunderstood topic, because people use words very loosely. The truth is very simple: a calorie is a measure of energy. It is the amount of heat energy necessary to raise one gram of water by one degree Celsius. We use calories to measure energy expended when doing physical activity, and we use it most often to measure the energy content of foods.

Why Pay Attention?

In terms of weight management, the formula is very simple: If you consume more calories than you burn off, your body will store the excess as fat. If you burn more calories than you eat, your body will get the extra energy by converting some of your body fat into energy. This is the essential point behind diets that simply want you to count calories.

So, to lose weight you can either decrease the number of calories that you eat, or increase the amount of calories that you burn. However, that simple rule is not so simple to apply.

How to Count

First, you have to know how many calories you're consuming. To get an accurate number, you have to read the nutritional facts label on all your food, and multiply the calories per serving by the number of servings you eat. Some food doesn't have labels, though, such as fresh fruit and vegetables. For those, you have to find the information from some other database.

However, as complicated as that procedure sounds, counting the calories you expend is even harder. To calculate that, you need to find your BMR or Basal Metabolic Rate. This is the number of calories you spend just to stay alive doing nothing else. Keeping your heart going, your brain functioning, your body temperature and your digestion are all part of your BMR. You can calculate it using this tool: BMR Calculator. To your BMR, you have to then add the number of calories you spend on every activity you engage in during your day. Again, you have to find a table or database that will tell you how many calories per minute (or maybe by distance) you spend, and multiply that by the amount of time you spent doing it. This is usually based on your current weight. As you can imagine, just trying to document every activity you perform during your entire day can be a challenge, not to mention the actual calculation.

The amount of bookkeeping work required for a calorie-counting diet is the reason why most people cannot bring themselves to stay on such a program. Besides, what if your numbers are off? Maybe you can have that slice of chocolate cake! It's easy to cheat yourself. Most people don't count too closely, and just try to eat less and exercise more. This is a good strategy, requires a lot less accounting work, but because it's so approximate, it's still easy to cheat, and there's no good way to keep track if you're too vague.

The Accurate Shortcut

You really have two choices when you approach a calorie-counting type of diet. You can accurately count the calories you eat, and assume your exercise is fine. Then, you eat fewer calories, and do the same amount of physical work each day. Or, you can accurately count the calories you burn and assume your food intake is fine. Then, you exercise more each day and try to eat the same. You can see that the first method will be easier and more accurate than the second because counting calories in food is easier than counting the calories in exercise. However, that's not the best way to lose the pounds and inches. The second way is by far the better approach. Read on...

If you cut the calories from your diet, and try to do the same amount of exercise, you will have less energy all day. You won't feel like walking fast and certainly not going to the gym. If you continue to cut more calories, your body will think that there is a famine, and try to conserve as much energy as it can, making you slow down and actually store more of the calories as fat. This is the dieting paradox, and it's a consequence of your body's excellent adaptation (to read more on Adaptation, visit my website).

On the other hand, if you know how much energy you expend during a typical day and work to increase that every day, but keep your eating habits about the same, then your body gets used to needing to spend more energy, and makes the energy available by burning fat more effectively. Doing exercise every day (preferably interspersed throughout the day) will also raise your BMR, so that you're burning more calories even while resting. Some research has even found that physical activity can suppress appetite, making your goal even easier.

The greatest benefits come when both sides of the equation are taken into account. Increase your physical activity a little bit each day, and control the number of calories you consume. For more on exercise and the benefits of physical activity, read my article on Exercise on my website.

Dangers

The big danger to cutting food out of your diet based solely on calorie count is that you may be getting rid of food that is very good for you for other reasons. Tuna is high in calories, but is an excellent source of protein, as well as essential fatty acids and many other nutrients. To cut that out would be a mistake.

Also beware what "diet" foods you buy that claim to be low-calorie. In the market, you'll find a lot of pre-packaged food that says "This product helps promote weight loss because it is portion-controlled (or calorie-controlled)" The only special design is that there's only a specific amount of food in the container so you can't overeat. A fat lot of good that does!

The other problem with simply controlling calories is that the body prefers to burn carbohydrates, especially blood-sugar, before burning fat stores. Your body creates fat for the purpose of storing it for the long-term. It's like putting money into a savings account. If you're just going to spend it right away, put it in your wallet. When your body makes a fat deposit, it is not intending to spend it right away. So just because you're taking away calories from your diet does not mean that your body will immediately burn fat at the same rate to compensate. Your body may instead just make you feel hungrier (read my article on Satiety on my website.) Or it may think that you're starving and make you more tired to prevent you from burning any more calories than you need to survive (again, my article on Adaptation can be found on my site.) For this reason, your choice of foods has to be based on more than just calorie-count.

The Negative Calorie Food Myth

This sounds good in theory, but is based on bad science. The idea is that it takes a certain amount of energy to digest foods, and that some foods have fewer calories than it takes to digest them. An apple is supposed to be a negative calorie food. An average apple is 100 grams and contains 44 calories. The theory is that is takes up to 100 calories to digest an apple, so digesting an apple is a weight-loss activity. The more apples you eat, the more weight you should lose. Those selling the Negative Calorie Diet don't phrase it like that, because when you state it in simple terms, it sounds insane. The fact is that the energy you use digesting is part of your BMR. If you stuff yourself, your body doesn't expend more energy digesting... it just continues at its normal rate and you get that "beached whale feeling". The only way to raise your BMR is to exercise more and to eat more frequently. So, this "special diet" is actually just counting calories, making sure that your calorie intake is less than your BMR + Exercise. There's no magic to their list of foods, they're just low-calorie foods, and they encourage you to eat them frequently. Don't waste your money on this scam.