A healthy diet is the basis for a well-functioning body. Food is the source of energy for all of our bodily functions and directly affects how our bodies and minds function in every stage of life. There are a variety of reasons why a healthy diet is important, including disease prevention, maintenance of a healthy weight and quality of life.
Calories are the unit of measure for stored energy in food. The energy provided by food calories is needed for every function of the body, including thought, physical activity, growth and healing. According to Medline Plus, foods containing an equal amount of calories and nutrients are ideal for a balanced diet.
Proteins, carbohydrates and fats are the building blocks of energy. After ingestion, carbohydrates are broken down into glucose, which provides raw energy that is either used immediately or stored in the muscles for later use. Complex carbohydrates like whole grains, vegetables and fruits provide a balance of calories and nutrients, whereas simple carbs such as sugar and white flour are high in calories and low in nutrients, making them a poor choice for energy production.
A healthy diet helps maintain an ideal body weight and prevent obesity. When eaten frequently, foods high in saturated fat, trans fat and sugar can lead to excess weight gain and obesity.
While calories are needed for energy, empty calories—those derived from foods with little nutritional value—can lead to weight gain. Eating foods with a balance of calories and nutrients can help provide the body with the fuel it needs to function while avoiding weight gain.
A poor diet has been directly linked with diseases such as diabetes, heart disease and certain types of cancer. Trans and saturated fats are known to cause atherosclerosis, which is a major risk factor for heart attack and stroke. Foods high in cholesterol can raise levels of LDL ("bad") cholesterol in the blood, which also contributes to the arterial damage seen in atherosclerosis.
According to the American Cancer Society, processed meats, fried meats and alcohol are associated with an increased risk for certain types of cancer, such as cancer of the colon or liver. Foods that contribute to obesity are also indirectly linked to cancer, since obesity increases the overall risk for developing cancer.
Mood and Cognition
A healthy diet can lead to better overall performance of the mind and body. According to the U.S. Department of Agriculture, foods high in antioxidants can help promote generation of neurons into old age while improving the ability of existing brain cells to communicate with each other, resulting in improved cognitive functioning.
What's more, diet may play an important role in mood and mental health. According to the American Journal of Psychiatry, a healthy diet is associated with a lower incidence of depression, anxiety disorders and dysthymia than a typical "Western" diet high in sugar, processed foods and alcohol.