There are many detrimental health effects of obesity: Individuals with a BMI (Body Mass Index) exceeding a healthy range have a much greater risk of medical issues. These include heart disease, diabetes mellitus, many types of cancer, asthma, obstructive sleep apnea, and chronic musculoskeletal problems. There is also a focus on the correlation between obesity and mortality.

It is common for dieters to have tried fad diets only to find that they gain weight, or return to their original weight, after ceasing the diet. Some improvement in patient psychological health is noted after bariatric surgery. Although diet, exercise, behavior therapy and anti-obesity drugs are first-line treatment, medical therapy for severe obesity has limited short-term success and very poor long-term success. Weight loss surgery generally results in greater weight loss than conventional treatment, and leads to improvements in quality of life and obesity related diseases such as hypertension and diabetes mellitus. The combination of approaches used may be tailored to each patient. Bariatric treatments in youth must be considered with great caution and with other conditions that may not have to be considered in adults. Techniques used in bariatrics include bioelectrical impedance analysis, a method to measure body fat percentage.

Intensive care is usually only offered to those whose condition is potentially reversible and who have a good chance of surviving with intensive care support. A prime requisite for admission to an intensive care unit (ICU) is that the underlying condition can be overcome.