Chapter 4 Carbohydrates from the book 'New Life through Nutrition' by Dr Sheldon C Deal

All food stuffs can be broken down into carbohydrates, fats, protein, vitamins, minerals and water. There isn’t anything edible that doesn’t contain one or more of these six elements. All foods are classified as carbohydrates, proteins or fats. Carbohydrates include starches, sugars, gums and dextrins. One gram of carbohydrate equals 4 calories, one gram of fat equals 9 calories, one gram of protein equals 4 calories.

A calorie is the amount of heat required to raise the temperature of a kilogram of water one degree centigrade. 80% of all food eaten is used to maintain body temperature. Roughly half your diet ought to be carbohydrate, 25% protein, 25% fats. A formula for figuring it out is to divide the body weight by 2.2 and multiply by 30. This gives you the number of calories you need each day if you expend only moderate amount of energy.