Dear Doctor Owen:

Excuse me, but I must be a dummy. In every article you talk about “calorie” this and “calorie” that. I thought the most important thing was fat. I count my fat grams and still don’t lose weight. What is a calorie anyhow?

Dummy

Dear “Dummy”:

Pardon me for not explaining this in earlier columns. Most of the patients I see are diet veterans, who know a lot about dieting and food. Your question reminds me that most of the world does not realize that excessive calories make us fat.

A calorie is the energy contained in food, which is released when burned by fire. It can be measured in a device called a calorimeter. It is possible to tell how many calories are in a piece of food by burning the food in the calorimeter, and even tell if it is primarily fat, carbohydrate, or protein by the weight and the energy produced.

The body does the same thing. It literally burns the food by a chemical process, and heat is produced, which fuels other chemical reactions. You need a certain amount of energy to run your body’s basic processes. Most energy needs of the body are derived from carbohydrate or sugar. Carbohydrates are mainly found in fruits and vegetables. Carbohydrates are literally sunlight and water, combined by photosynthesis in plants. Refining these plants gives us simple sugar, breads, pasta, and other tasty items.

The body’s building blocks are usually made of protein, which can be used as energy by converting it to carbohydrate, if a deficit of carbohydrate occurs. Protein can also be converted to fat if too much of it is found in the diet for basic needs. Muscle is made of protein, so the majority of protein eaten in the United States is meat. Protein can also be found in some vegetables such as dried beans (legumes).

Fat is used for energy if a deficiency in carbohydrate occurs (e.g., when we diet). It can be used straight from the diet or stored in fat cells for future use. Fat is broken down from fat cells, which are taken to the liver and converted to carbohydrates before the fat is used for energy. Fats can be found in plants or animal foods. Nuts, olives, corn, and avocados are examples of high-fat vegetables. These are unsaturated fats, which have the same calories as saturated fat. Unsaturated fat may not be as harmful as saturated fat to the arteries, unless it is taken in excess.

Alcohol, by the way, goes directly to fat. It does not pass “Go” nor does it collect $100.

If more calories are eaten than are needed for organ function or muscle work, the body efficiently stores up the excess as fat. Because excesses were rare in nature, our ancestors became very efficient at storing fat. Because the muscular work of day-to-day living has steadily declined, the energy needs of the average person have, in turn, declined. Combined with easy access to tasty food and drink, most Americans consume more calories than they need for survival.

Carbohydrates contain 4 calories/gram of food; protein also contains 4 calories/gram; but fat contains 9 calories/gram. Therefore, it is easy to see how quickly one can exceed his or her daily needs when fat content is high. Fat is also very tasty and dense (non-bulky), so it is difficult to “tell” when to stop eating. Most people stop eating only when the discomfort of a tense stomach is worse than the reward of the food.

Individual differences in the ability to feel full and to stop eating are known as satiety, and vary greatly from person to person. Protein seems to be the most satiety-inducing food, followed by fat, and then by carbohydrates. Most protein is found in meats, which are also high in fat (with the exception of seafood).

Most starches are made from vegetables and, therefore, are carbohydrates—such as potatoes, rice, and pasta. Simple sugar, like that found in soft drinks and snacks, is more concentrated than that found in complex forms, such as in vegetables, where it is bound up with fiber (cellulose). Therefore, one can consume many more calories from starches and sugar without any bulk and never feel “full.” I am always amazed at what little awareness people have of the calories in soft drinks. Many patients who say they do not eat anything—but are overweight—drink their calories in soft drinks, juices, and milk—all dense calorie items.

The reason dietitians urge people to eat more complex, unrefined carbohydrates—such as whole fruits and vegetables, lean meats, and very little fat—is simple: Bulky, low-fat foods tend to fill the stomach faster with fewer calories. Items that say “no fat” still have plenty of carbohydrates in a very dense package. Items that say “no fat, no sugar” really mean no simple sugar, and are loaded with complex carbohydrates, at 4 calories/gram.

No matter how well you understand calories, it never hurts to read labels, note the texture and weight of food (fat is heavy, floats, and is greasy to the touch), and learn how to balance the taste reward of food with the desire to live healthier and longer. The challenge is how to exploit the senses without doing harm.

What a wonderful place this earth has become! Our major health concern is. . . too much pleasure. Give that some thought!