Nutrition physiology is the study of food’s effect on the human body’s ability to sustain the chemical and physical processes that are necessary for biological life functions. These chemical and physical processes that take place in the body are what is known as metabolism. Body metabolism is influenced by the consumption of protein, carbohydrates and fats, as well as by many vitamins and minerals.
The science of nutrition physiology actually is an old science. Hippocrates, the ancient Greek physician, was aware of the effects of food on the body. In general terms, the consumption of food serves a twofold purpose for the human body. First, it provides the source for energy, which is measured in calories. Secondly, food assists the multitude of chemical functions required to sustain life.
Carbohydrates, proteins and fats affect metabolism in different ways. The body easily absorbs carbohydrates and uses them as a main energy source for muscles and the central nervous system. Protein is utilized to produce important biochemicals such as hormones that regulate body functions and to produce antibodies to fight disease. Fats can be stored by the body as energy. They also help regulate body temperature and protect certain organs.
Vitamins and minerals are called micronutrients, and they enhance a variety of specialized body functions. For example, vitamin B1 is important for nerve cells. Vitamin C helps the liver detoxify harmful substances, and the body also uses vitamin C to manufacture collagen, the protein that is found in skin and other body tissue. Trace minerals are important as well. Chloride is important for the manufacture of stomach acid, and the thyroid needs iodine to produce hormones.
Human metabolism works in two stages. After the consumption of food, the body’s metabolism enters the absorptive stage in which nutrients are broken down and stored. During the post-absorptive stage, the body puts nutrients to work.
Nutrition physiology studies have examined the effects of food on aging, disease, mental health and body weight. Obesity is a major concern and is often considered a precursor to heart disease, diabetes and cancer. In addition, obesity can have major psychological and social effects.
Energy outlay and food consumption must remain equal to maintain a healthy body weight. A person gains weight when he or she consumes more calories than his or her body requires. A lack of exercise and an over-abundance of readily available, over-processed foods have been cited as some of the causes for obesity.
Nutrition physiology is an important issue for athletes, and sports experts have developed various nutrition systems aimed at enhancing performance in sports. High-carbohydrate diets are often recommended for athletes. Protein can help athletes recover from intense training and competition. Nutrition experts also recommend sufficient fluid intake for everyone, not just athletes, because fluid intake has a significant influence on the body's metabolism.