If you want to lose weight, you must eat less than what your body needs for cell repair and to burn for energy. If you eat more than what your body needs, the excess food may be stored as muscle, but, mostly, it is stored as fat. Counting calories will make it easier to lose weight during a diet. If you know the calorie content of food, you can avoid high-calorie foods and select lower-calorie foods that allow you to lose weight and satisfy your nutritional requirements.
What is a Calorie?
A calorie is the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius. The calories in food are really kilocalories or 1000 calories. When we say that a carbohydrate like sugar has 4 calories per gram, we really mean that it has 4 kilocalories per gram. This means that one gram of sugar has enough energy to raise the temperature of 1000 grams of water by 4 degrees Celsius. The calories in food provide a measure of the energy content of the food.
How many calories does your body burn?
The number of calories that you need depends on the size of your body and your level of activity. A large person requires more calories than a small person, an active person requires more calories than a sedentary person, and men require more calories than women. The minimum amount of energy required when resting, called the Basal Metabolic Rate (BMR) can be calculated using the Mifflin-St Jeor equations. These equations require the weight in kilograms, the height in centimeters, and the age in years. The BMR has to be multiplied by an activity factor to estimate the daily calorie requirements. The following calculator can provide an estimate of your daily caloric requirement, but it is important to provide a good estimate of your activity. "Sedentary" means that you don't exercise at all. "Lightly active" means that you engage in light exercise or sports 1-3 days per week. "Moderately active" means that you exercise hard at least half an hour per day, five days per week. "Very active" means that you engage in fairly strenuous exercise or sports 6-7 days a week, and "extra active" means that you have a physical job where you are very active throughout the day.
Setting a Target Body Weight
Once you have calculated your current calorie requirements, you have to calculate the calorie requirements for the body that you would like to have. Your target weight should be such, that your Body Mass Index falls within the normal range of 18.5 to 24.9. For example, if you are a 35-year old, lightly-active female with a height of 5 feet, 6 inches and a weight of 160 pounds, you need 1,978 calories per day to maintain your weight. If you want to weigh 145 pounds, set the weight in the calculator to 145. The calculator shows that you should eat 1,884 calories per day to maintain a weight of 145 pounds. This difference of about 100 calories per day is equivalent to a slice of toast with a pat of butter.
Since one pound of body fat has about 3,500 calories, a reduction of 100 calories per day will cause the loss of one pound of weight in 35 days. By just cutting out the calories equivalent to one slice of buttered toast from your diet, you can lose 15 pounds in one year and a half. Similarly, you can gain 15 pounds in a year and a half by eating 100 calories extra per day.
Weight loss can be accelerated by reducing the calories further, but a diet should not reduce intake below 1,300 calories per day because such diets are not sustainable and it is very difficult to obtain all the necessary nutrients with very low calorie diets. Another adverse effect of very low calorie diets is that the body goes into starvation mode and decreases the BMR. A decrease in BMR reduces weight loss and has the unfortunate consequence that you will gain weight faster if you overeat because you will be consuming more excess calories above your new, lower BMR.
The best diet is one that can be maintained for many months or years until healthy eating habits become a way of life. As a general rule, your daily calories should not be reduced below 15 percent of the calories required by your target weight and activity level. In our example above, the target weight for the lightly active female requires 1,884 calories per day. Fifteen percent of this amount is 282 calories, i.e, 1884×(15/100). Subtracting 282 from 1,884 we get 1,602 calories per day. This reduction of 282 calories per day should result in the loss of one pound every twelve days, or about 2 pounds per month, at the beginning of the diet. As the body weight decreases, the rate of weight loss will also decrease. When you approach your target weight, you can increase your calories gradually until you reach a maintenance level.
Just how much food is 282 calories? This is approximately one slice of apple pie (1/6 of an 8-inch pie), or one jelly-filled doughnut, or two scoops of vanilla ice cream, or two regular sodas. You can normalize your weight by just skipping dessert and sweet drinks! It also helps if you can exercise vigorously 30 minutes per day. Vigorous exercise can burn 200 calories in half an hour. Just walking burns approximately 150 calories in half an hour.
Determining the Calories in Food
Once you know how many calories you need to achieve your target weight, you have to figure out how many calories are in the food that you eat. The following table shows the calories of carbohydrates, proteins, fats, and alcohol. Fiber consists of carbohydrates that are not digestible and can be subtracted from the amount of total carbohydrates.
|Carbohydrates||4 Calories per gram|
|Proteins||4 Calories per gram|
|Fats||9 Calories per gram|
|Alcohol||7 Calories per gram|
Since most foods consist of complex mixtures of the basic food components, you will need to interpret nutrition labels to determine the calories in packaged foods, and you will need five basic tools:
Establish a baseline: If you are not used to dieting and measuring food, the best way to start is to just eat normally for about one week, but weigh and measure everything that you eat or drink. This will establish a baseline of your normal eating habits and your ad libitum caloric intake.
As an example, let us say that you would like to eat some sunflower seeds. The nutrition label says that one serving consists of one ounce or 28 grams, and that the one-pound package has 16 servings. This 28-gram serving has 190 calories. Grab a handful containing all the sunflower seeds that you are going to eat, and before eating a single kernel, weigh them. Suppose that they weigh 30 grams. You know that there are 190 calories in 28 grams, so you calculate:
You write this in your journal and then you can enjoy the seeds.
Once your diet starts: You will want to know how many grams of food have a specific number of calories. If you want to eat only 100 calories of sunflower seeds, how many grams should you eat? Since you know that 28 grams have 190 calories, you can calculate:
Round this figure to 15 grams, weigh that amount of seeds, write it in your journal, and enjoy knowing that you are eating only half of your previous calories. You may still feel hungry, but that is life. You have to sacrifice for what you want. You won't starve.
The first few days of keeping track of your calories are the hardest because you have to look up the number of calories of each new food. It may seem that you are spending more time writing down what you eat than eating. Don't be discouraged.
Scales and Software to make your life easier
There are scales such as the Newline Digital Nutrition Diet Scale that weigh and track nutritional intake for many foods. All you have to do is select the name of the food, and the scale calculates the calories, fat, cholesterol, fiber, and protein based on the weight. The scale can store in its memory multiple food entries to keep a record of what you have eaten.
There are several web sites and computer programs that you can use absolutely free to determine the calories in food and to track your daily calories and nutrients.
Main topics covered in this page:
Calorie counting is an easy way for you to manage your weight.
Learn how to calculate your daily calorie intake and how to count calories to lose weight.
Calories count when it comes to weight loss.
The energy in food is measured in units of Calories.
What are calories and how to count them.