Читать книгу Nutrition For Dummies - Carol Ann Rinzler - Страница 66

When someone says that a serving of food — say, one banana — has 105 calories, that means your metabolizing the banana produces 105 calories of energy your body can use for work.

Different foods have different amounts of calories depending on their nutritional components. For example, high-fat foods have more calories than low-fat foods because a gram of fat has more calories than a gram of carbs or protein or alcohol:

 Protein has 4 calories per gram.

 Carbohydrates have 4 calories per gram.

 Fat has 9 calories per gram.

 Alcohol has 7 calories per gram.

In other words, ounce for ounce, proteins and carbohydrates give you fewer than half as many calories as fat. That’s why — again, ounce for ounce — high-fat foods, such as cream cheese, are calorie-rich, while low-fat foods, such as fruits and vegetables, are not.