Food is any material consumed to provide nutrition to an organism. In humans, food is composed of all edible parts of plants and animal tissues, and includes all vitamins, proteins, carbohydrates, and fats. There are two categories of food: dietary food for protein consumption; and industrialized food for growth and development. The primary difference in the classification is the source of nutrition. Plants contain carbon dioxide, water, and nutrients while animals contain only flesh and bones.

To analyze food, we need to know what it is, how it is formed, how it is stored, how it is used and by whom, before we can judge its nutritional quality. A part from all the food that we consume, we get two main groups: living and non-living matter. Living food is the primary source of nutrition, including all the elements that compose it (the soil being the only exception). Non-living food is that which is not living, such as plants and animals meat, fat, milk and sugar. There is a considerable difference between the quality of living food and non-nutritious food.

The quality of the diet depends on the proportions of the different kinds of food. Each one of the components should be equally distributed over the diet. Fruits, vegetables and other light and green foods make up the richest part of the diet, with cereals, whole grain breads, pastas and beans making up the remaining portion. Pasta, beans and lentils are regarded as bad for health, because they contain excess sugar. Sugar intake should be kept to minimum, because sugar is considered one of the most important causes of diseases.

Another factor affecting the food choices is the habit of people to consume it more often than required, leading to irregular food patterns, and thus an irregular intake of the right amount of nutrients. Eating a large quantity of food in less than the required times may cause vitamin deficiencies and other health problems. Nutrition is also affected by the frequency of food consumption. Some of the foods that help prevent good health include drinking water, avoiding trans fatty acids in the diet and eating organic food.

Animal meat should be used in limited quantities, because it is full of cholesterol, which is considered harmful, especially in women who have high blood cholesterol levels. It is good to choose poultry and fish for proteins, carbohydrates and vitamins. Other important foods that help prevent good nutrition include dairy products, fruits, vegetables and grains.

It is always advisable to see food labels before purchasing it. It helps you to understand the nutrients contained in various foods. It is important to read labels carefully. The nutritional content of many foods varies according to the type of food, so one should be careful about choosing foods without added fats or sugars.