Healthy eating can help you have a healthy weight. Being under-or-over-weight can increase risks to your health and wellbeing.
People who are underweight have a higher risk of getting infections, developing brittle bones (osteoporosis) and infertility (difficulty getting pregnant). Being underweight can be caused by an eating disorder such as anorexia and illness such as cancer.
People who are overweight or obese have a higher risk of developing a wide range of diseases and conditions. These include type 2 diabetes, heart disease and stroke, high blood pressure, some types of cancer—breast, endometrial, colon, prostate and kidney, and others.
Childhood obesity affects growth and development, and contributes to long-term health problems. Overweight young people may also feel bad about themselves. This can affect school performance and how they get along with others.
What we eat affects our weight. A person's weight depends on 'energy in' (eating) and 'energy out' (activity). Energy is measured in calories. The body uses calories to sustain life—breathe, pump blood, replace cells, digest food, etc. The body also uses calories for the basic tasks of living—dressing, eating, bathing, walking, climbing stairs, working, playing, etc.