Meat and vegetables are measured in grams and kilograms. Milk and other liquid foods are measured in liters or milliliters. These units only measure quantity: they do not measure the value of the food to the body. The unit which measures the quality or value of food is the calorie the amount of heat given off by food when it brurns. This measurement tells how much energy a certain food has when it is completely used by the body. Our bodies use varying  amount of calories. The more exercise we take, the more calories we burn. If we eat food which contains more calories than we use up, then it is possible that we would increase in weight. In order to avoid becoming overweight, it is advisable to eat a balanced diet and not eat too many foods that have a high calorie rating. The table below gives you some idea of the number of calories in food. Which is the best title of passage?
How to Measure the Quality of Food Calories in Foods The Units of Measurement How to Keep Fit