Increasing education efforts, accessible weight management plans and foods, and a growing desire to be physically desirable have fueled this market in more recent years. More than 100 million people in the United States are actively involved in a weight loss or weight management plan at any one time throughout the year. This suggests a demand for products and services which will continue for years to come.
The definitions or measurement characteristics for overweight and obesity have varied over time. The varied definitions affect prevalence statistics and make it difficult to compare data from different studies. The prevalence of overweight and obesity is commonly assessed by using body mass index (BMI). A BMI over 25 kg/m2 is defined as overweight, and a BMI of over 30 kg/m2 as obese. These markers provide the common benchmarks for assessment, but the risks of disease in all populations can increase progressively from lower BMI levels.
According to the World Health Organization, adult mean BMI levels of 22-23 kg.m2 are found in Africa and Asia, while levels of 25-27 kg.m2 are prevalent across North America, Europe, and in some Latin American, North African and Pacific Island countries. BMI increases among middle-aged elderly people, who are at the greatest risk of health complications. In countries undergoing nutrition transition, overnutrition often coexists with undernutrition. People with a BMI below 18.5 kg/m2 tend to be underweight.