Clinical nutrition is the study of the connection between your body’s overall state of wellness and the foods you eat each day. If you go beyond the details of how diet affects health — how particular nutrients can produce particular health outcomes or what kind of diet most effectively helps you reduce your risk of developing diseases like diabetes, heart diseases, hypertension, and so on — you realize that what you eat really matters.

From the cruciferous vegetable family (home to foods like cabbage, broccoli, cauliflower, and brussels sprouts), kale has enjoyed a surge in popularity in the past few years. Evidence suggests this superfood wards off cancer, helps regulate blood cholesterol levels, reduces the risk of heart disease, and promotes eye health.

Exercise is one of the best things you can do to foster a long, healthy life. Regular, even vigorous, exercise has a positive effect on your overall fitness. It helps you maintain a healthy weight; improves your cardiovascular health, brain functioning, and more; and helps prevent the development of conditions like diabetes, heart disease, stroke .

The digestive system processes the fuel your body needs for survival. This system is one of the most important in your body because it is connected to and works in tandem with almost every other body system. When your digestive system isn’t working properly, you can experience an almost endless series of physical and even mental health effects.

Health behavior theory is a field of public health science that tries to deconstruct human behaviors to see why people do the things they do. In other words, it’s a way to evaluate behaviors to uncover what influences them. Using health behavior theory techniques can make your attempts to help others (or even yourself) change health and wellness habits more effective.

Carrots are filled with beta-carotene, a plant pigment that gives color to vegetables such as carrots, mangoes, and yams. Leafy greens are another major source of this antioxidant. Beta-carotene is the most common and well-known member of the carotenoid family. Carotenoids are compounds that the body converts into vitamin A.

Many people take supplements to ensure that they’re getting the right amount of vitamins and minerals and to improve their health. Yet many researchers are on the fence about just how beneficial supplements are and, even more importantly, how safe they are. The following sections identify four of the more popular supplements — multivitamins, fish oil supplements, meal replacers, and energy drinks — explain what each is used for, and summarize what the science says about each supplement’s effectiveness and safety.

A poor diet — one that is high in fat and sugar and low in fiber and nutrients —puts you at risk of developing a variety of preventable diseases and health conditions, like diabetes, high blood pressure, and more. The following table summarizes some of the most prominent health risks associated with poor dietary habits, identifies the dietary component that increases your risk, and offers some tips on how you can change your diet to reduce your risk.

According to health behavior theory, sooner or later, the decisions you make now will determine your health and wellness status well into your future. A collection of many variables unique to each individual — his or her perceptions, values, personality, beliefs, habits, cultural influences, family history, and so on — affect disease prevention, health maintenance, and treatment choices.