On a global scale, it is estimated that 1,6 billion adults are overweight and at least 400 million adults are obese. Furthermore, the prevalence of obesity is increasing, especially amongst children and adolescents. When energy intake exceeds expenditure, the excess calories are stored in adipose tissue, and if this net positive balance of energy is prolonged, it can lead to obesity. Adults are considered overweight if their body mass index (BMI) is 25-29.9, and obese if the BMI is 30 or more. The BMI is calculated by dividing a person's body weight in kilograms by the square of his or her height in meters (kg/m2). Cardiovascular diseases (CVDs), diabetes, arthritis, sleep, breathing
disorders, depression and cancer are some of the diseases closely associated with obesity.