The food we eat contains various nutrients that are digested differently:
- Carbs (carbohydrates) are broken down into glucose, which provide the main source of energy for the body (brain, organs, muscles and other tissues). Carbs are found in grains (cereals, pasta, rice, bread, etc.), legumes and beans, fruit and vegetables. Carbs are broken down in glucose in the blood stream; with insulin, glucose can be absorbed by the body. Diabetes diseases prevent a proper absorption of glucose, either because insulin is no longer produced (Type 1 diabetes) or because the body resists it (Type 2 diabetes).
- Fibers are essential for digestion and provide numerous health benefits, such as reducing appetite, regulating blood glucose, reducing risks of cardio-vascular diseases and cancer. Fibers are carbohydrates (carbs), but they are not being absorbed themselves (they simply pass through).
- Proteins are amino acids that provide the building materials for the body to grown and maintain its structure. There are two types of amino acids: essentials and non-essentials. Essentials amino acids must be consumed to be present in our body; non-essential amino acids can be built within our body. Proteins come from animal or plant sources. Animal sources (meat, dairy, eggs, cheese) provide all essential amino acids, and are often referred to as complete proteins. Individual plant sources (grains, nuts beans, vegetables) do not provide all of them, but combining different plant sources does.
- Fats are found in oils, butter, etc, but also in most natural food such as vegetables (usually in very small amount). Fat is an essential nutrient; it helps absorbing vitamins, provides fatty acids required for body structure and is a good source of energy at 9 calories per gram, twice as much as carbs (4 calories/gram) and proteins (4 calories/gram). There’s currently various debates about health benefits of the different types of fat: although it widely accepted that saturated fats are unhealthy, some say that any types of fats, including monounsaturated and polyunsaturated fats, are equally unhealthy, a claim opposed by others. The Dietary Guidelines for Americans suggests that up to 30% of the energy should come from fats, a value that is considered too high by many.
- Vitamins (A, B, C, D, etc.) are nutrients that the body needs to properly work. Vitamins are found in natural food and routinely added in processed food (e.g. milk with vitamins A and D). A balanced diet usually provides all of them in sufficient quantities, but since there’s no clear definition of what a balanced diet is, and since people are eating differently, vitamins are routinely consumed (if not over-consumed) as supplements.
- Minerals (calcium, iron, etc) are elements needed to maintain the body structure. All of them are found in the food we consume. Since different people eat different food, mineral supplements are often taken by many.
- Water is the underdog of nutrition. It cannot be stated enough how water is essential for the body (itself made of 60% water) to work. The basic requirements of 8 glasses a day can easily be doubled or tripled for added benefits. Water is essential for the body to work. The kidneys auto-regulate the exact amount the body needs and flush the extra along toxic by-products resulting from digestion. The lack of water leads to dehydration. Mild dehydration makes us feel tired, gives us headaches, etc. Severe dehydration leads to very serious complications. It is estimated that over 70% of Americans (including preschoolers) are mildly dehydrated.