Carbohydrates are foods which are transformed (after digestion) into glucose. The GI (glycemic index) measure the capacity of the carbohydrates to increase the glycemia (glucose released in the blood). This is why only carbohydrates can be given a GI. In this category are classified the starch and sugars: flours (bread) grains, cereals, potatoes, rice, fruits, green vegetables, sugar, and dry legumes (lentils, peas, soy, chick peas…). - The proteins: they are the essential building blocks of human body, but they also have various functions. They for instance contribute to the sensation of satiety. Proteins are found in all meat (poultry, beef, mutton, pork…) fish as well as eggs and cheese. - The lipids: they are the fatty acids which can be found in animal products (butter, cream...) but also in many vegetables (oil). However, carbohydrates, proteins and fat can be found together in most food, for instance in milk there are fats as well as carbohydrates (lactose) and protein. Most cereals are alike, but we consider they are carbohydrates because starch is the main portion of it.