What is the difference between being overweight and being obese? We examine the raw medical facts

Definition
Obesity is defined for weight to height ratio greater than 30 kilograms per metre squared (BMI greater than 30). This is usually due to greater energy intake than output.

Causes
The majority of causes are due to overeating. This may be related to the wide availability of cheaper and more varied foods of a less nutritious value (increased fat). Overeating due to anxiety may also be a factor. People are also expending less energy due to the increased popularity of sedentary pastimes such as watching television, or using personal computers. More people use cars as opposed to walking and fewer people take regular exercise. There is an association of obesity within families and this may be partly genetic and partly due to lifestyle. There are secondary causes of obesity due to hypothalamic conditions that increase the appetite, and also endocrine disorders. However these are uncommon. The most common causes of secondary obesity are hypothyroidism and Cushing's syndrome.

Symptoms and signs
The majority of patients will complain of shortness of breath during mild exercise, or pain in the back, hips or knees caused by the increased weight. The patient may also suffer symptoms of the complications of obesity, such as gallstones, varicose veins or heart disease. A great many patients find the greatest symptom to be social embarrassment.

Complications of the disorder
Most of the medical complications of obesity are well known. The risks of associated diseases increase the mortality rate when combined with obesity. Associated problems are sleep apnoea, cancer, diabetes mellitus, cerebrovascular disease, coronary heart disease, hypertensive incidents, respiratory disease, gallstones, hernia, arthritis and varicose veins.

Tests
For diagnosis, the body mass index is normally made by comparing the patient's height to weight ratio. Blood tests may be taken to exclude secondary complications such as raised cholesterol, and tests for diabetes may be undertaken. Doctors may also assess the heart by performing an ECG.

Treatment

Medical
Medical treatment is aimed at not only treating any complications of obesity but also trying to reduce weight by tackling diet and lifestyle. The aim of weight reduction is to reduce weight by around one kilogram a week until the desired BMI is reached. The mainstay of treatment is reduction in energy intake, especially from fat, sugar and alcohol. Usually the help of a dietician is beneficial. Physical exercise to increase energy output is encouraged, but on its own is ineffective. Medication to aid weight loss has become increasingly popular of late, but careful patient selection is critical for its success. The patient has to be genuinely interested in losing weight prior to using medication.

Surgical
In gross obesity, gut bypass surgery may be necessary or indeed gastric stapling and jaw wiring. An apronectomy to remove excess skin after weight loss is sometimes indicated but is not an effective initial surgical solution.

Long-term education regarding the risks and complications of obesity is necessary and patients frequently need active encouragement. The use of dietary clubs is sometimes helpful.

This information was supplied to iVillage by Medic Direct