Obesity, Diet Management & Nutrition

Basic Science of Obesity and Overweight

Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health, leading to reduced life expectancy and/or increased health problems. In Western countries, people are considered obese when their body mass index (BMI), a measurement obtained by dividing a person's weight by the square of the person's height, exceeds 30 kg/m2, with the range 25-30 kg/m2 defined as overweight. In earlier historical periods obesity was rare, and achievable only by small elite, although already recognized as a problem for health. But as prosperity increased in the Early Modern period, it affected increasingly larger groups of the population. In 1997 the WHO formally recognized obesity as a global epidemic. As of 2008 the WHO estimates that at least 500 million adults (greater than 10%) are obese, with higher rates among women than men. The rate of obesity also increases with age at least up to 50 or 60 years old and severe obesity in the United States, Australia, and Canada is increasing faster than the overall rate of obesity.
Once considered a problem only of high-income countries, obesity rates are raising worldwide and affecting both the developed and developing world. These increases have been felt most dramatically in urban settings. The only remaining region of the world where obesity is not common is sub-Saharan Africa. Obesity is a complex disease resulting from the interactions of a wide variety of hereditary and environmental factors. The combined progress in quantitative genetics, genomics and bioinformatics has contributed to a better understanding of the genetic and molecular basis of obesity.