Obesity is the epidemic of the 21st century, considered the largest nutritional disorder in Western countries. The World Health Organization (WHO), confirmed it to be the largest unacknowledged public health problem society has faced. It is a chronic disease with a huge prevalence in developed countries, although developing countries have seen significant growth in obese people. Furthermore, it affects men and women of all ethnic and age groups, reduces quality of life and has high rates of morbidity and mortality. Obesity is a disease that constitutes an important risk factor for the onset, development and worsening of other diseases. For diagnosis in adults, the most commonly used parameter is body mass index (BMI). BMI is calculated by dividing the patient's weight by height squared. It is the standard used by the World Health Organization (WHO). A person who has a BMI of 30 or more is generally considered obese. The World Health Organization defines obesity as the excess accumulation of body fat in adipose tissue, with implications for human health. There are many causes of obesity. However, excess weight is fundamentally linked to bad eating habits, a sedentary lifestyle resulting from poor physical activity and genetic factors.B1 People with bad eating habits often eat too much sugar and fat, but do not include fruit and vegetables in their meals newspapers frequently. Excess fats and sugars provide additional energy to the body. If the level of exercise is not sufficient to burn all the excess energy, the fat ingested will be stored as body fat. Excess weight occurs when a person's diet provides more energy than their body needs. People who stay with these linger for long periods... middle of the paper... the individual must undergo and follow strictly. Whatever the degree of obesity, it arises from the combination of internal predisposition with external factors such as poor eating habits and lack of physical activity. In greater or lesser proportions, both factors are always present. Under these conditions, weight loss must begin with a restoration of metabolism; also, change of habits. This requires very consistent hard work. Since then, the body energy imbalance that resulted in the excess kilograms has taken months or years to develop. For this reason it takes a long time to follow the reverse path that would lead to weight loss. People should not believe pills, miracle diets or sellers of extraordinary capsules. Objective knowledge, common sense and determination through the re-education of eating habits are certainly the best guarantees of success.