The ABC’s of Calories…Turning Food into Energy


When reading about weight reduction, there are lots of special terms and phrases that get tossed around, and quite frankly it can feel like you need a Ph. D. in nutrition just to figure out how to lose weight. The good news is it’s not that complicated if you learn the meaning behind the lingo.

What Is a Calorie?

For instance, we’ve all heard the term calorie, but if you ask most people they probably wouldn’t be able to tell you what a calorie actually is. The average person knows that caloric information is on the back of nutritional labels on packaged foods and if you intake too many calories, you’ll become fat. If that’s the extent of your knowledge, it’s okay. You’re not alone.

Contrary to popular opinion, a calorie is not a component of food, like protein or fat. In other words, a calorie is not a nutrient. Rather, it’s the amount of energy needed to raise the temperature of one gram of water by 1 degree Celsius.1

We know what you’re thinking: “What in the world does that mean?” Simply put, the calorie is just a unit that measures the amount of energy from food. So don’t worry about the technical scientific terminology. When you hear or read about calories, think energy from food which fuels your body.

We get calories from carbohydrates, proteins, and fats, as these are the energy rich elements in food. According to the scientific data, carbohydrates and protein contain four calories per gram of food, while fat contains nine calories per gram of food.2 You can observe the high level of caloric energy in fatty food, for instance, if you grill a fatty steak or hamburger patty. When the fat drips off the meat and into the flame, it causes the flame to flare up. That’s because these meats are relatively high in fat, which in turn is high in caloric energy.

How Food Becomes Energy

So how does your body convert the food you eat into energy? In its undigested form, the food you eat is too chemically complex to be distributed throughout your body as energy. That’s why when you consume food your digestive system adds chemicals and fluids which break down the food into useable nutrients. These nutrients, then, travel through the blood stream to the cells in your body, providing your organs and muscles with the caloric energy they need to function.

It’s a common myth that calories are bad. Calories are vital for life because they provide the energy from food which allows your body to continue running. Everything from the movement of your muscles to the activity of your cells requires caloric energy. The problem is when you eat more calories than your body needs to function. Your body then stores the extra calories as fat.

Calories and Weight

Websites and bookstores are flooded with information on “secrets to weight loss.” In reality, weight loss isn’t a secret; it’s incredibly simply. According to nutritionists, you gain weight when you take in more calories than your body needs for energy; you lose weight when you burn more calories than you take in through your food.3 It’s as simple as that.

It’s easy to see why a low calorie diet and regular exercise are two essential components to weight reduction. A low calorie diet will limit or eliminate the intake of extra calories which would otherwise be converted into fat. And exercise will cause your body to burn any extra calories you do consume, and it will cause your body to burn calories that have already been stored as fat. The end result is weight loss.

So in order to lose weight you have to be aware of how many calories you consume, and regulate your caloric intake so that you’re burning more calories than you’re taking in. That doesn’t mean you have to count every calorie you consume and write it down in a notebook. But it does mean that you need to have a general idea of how many calories you need in order to maintain a healthy weight and you need to have an idea of the caloric value of the foods you eat. Keep in mind that a pound of fat is equal to 3500 calories.

The caloric intake of each person is different because each person has a different body frame and each person participates in different levels of physical activity. However, as a general rule, women should eat somewhere between 1500 to 2400 calories per day; and men should intake somewhere between 2000 to 3000 calories per day.4

If you want to lose weight you need a low calorie diet that is on the lower end of the caloric range mentioned above. That means you have to start making better food choices. Avoid foods with “empty calories,” that is, foods with a lot of calories but little to no nutritional value, such as sodas and candy. Also, limit the intake of foods with excessively high calories like fatty meats, fried foods, candy, and fatty desserts.

That doesn’t mean you have to starve yourself in order to lose weight. It just means you have to increase your consumption of healthy, low calorie foods. For instance, vegetables, fruits, whole grains, and lean meats like chicken are great low calorie, nutrient rich foods.

The more you’re aware of how food affects your body, the better equipped you are to make healthy food choices and start an exercise program. You now know one of the most important elements of weight reduction, namely, calorie control. With the information you’ve learned here, you can now be aware of your caloric intake and determine what kind of diet and exercise program is right for you.


1 Bobick, J., & Balaban, N. (2008). The Handy Anatomy Answer Book.Canton,MI: Visible Ink Press.

2 McArdle, W., Katch, F., & Katch, Victor. (2007). Exercise physiology: energy, nutrition, and human performance.Baltimore,MD: Lippincott Williams & Wilkins.

3 Brown, J. (2010). Nutrition Now. Cengage Learning.

U.S. Department of Health and Human Services. (2010). Dietary Guidelines for Americans 2010.Washington,DC:U.S. Government Printing Office.


The content provided on this site is for informational purposes only. Our content is not medical advice and you should seek a licensed physician or health professional regarding all health issues. WEIGHTLOSS.US takes no responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, or application of medication which results from reading this site.