Food is any material consumed in order to provide nutrition to the organisms. Generally, food is of animal, plant or fungi origin, and typically contains necessary nutrients, including proteins, carbohydrates, vitamins, or other minerals. In a human diet, the main components are protein, fat, carbohydrates and water. The average person needs about 70% of the calories they take in every day in order to maintain their weight. The protein, however, is the most important nutrient, because it is needed for building muscle tissue, which is what makes up muscle mass. Other important nutrients include vitamins A, B, C and E, which are considered the essential vitamins that contribute to good health.

In this study session 2 nutrition talk, we will discuss food source databases, nutrient composition tables and food analysis. First, the food source database divides foods into specific groups, based on where they can be found, including: plant sources; animal and fungi sources; and microorganisms (which includes bacteria and other unicellular organisms). The nutrient composition tables show the percentages of different nutrients found in the food, as well as the recommended daily allowance (RDA) and estimated average requirements for each nutrient. For carbohydrates and fats, the recommended daily allowance for these nutrients is 40% of the total calories you take in, while the recommended percentage for carbohydrates is about 5%. The protein intake for the U.S. diet is the highest in the world, at about 8 grams per day.

The last topic we will touch upon in this primer on food sources and nutrition is food chemistry, which refers to the way that different nutrients interact with each other and how they affect the balance of nutrients in your body. A balanced diet is one in which the food you eat provides all of the nutrients necessary for your body; a bad diet is one where any excess nutrients are stored in the body as fat. In addition, there is a relationship between the balance of fat and folate levels in the blood and the risk of heart disease, certain types of cancer, high blood pressure and diabetes.