The diagnosis of obesity is based on the physical examination and medical history of the patient. It is important to calculate the BMI to confirm that it is greater than 30 kg/m2, in order to determine the severity of the obesity. This information helps establish the treatment goals and to determine if there are any health problems or risk factors.
Clinical history. It is of special relevance to obtain information on body weight history, age at onset, weight fluctuations, previous treatments, diet patterns, determining factors of the weight gain, medications that may have an influence on the variation in weight, and physical activity level, as well as a family history in order to assess the predisposition to certain diseases such as type 2 diabetes, and arterial hypertension. The history also helps us to identify other metabolic diseases associated with obesity, as well as to determine the level of control of the known health problems. Finally, the history of smoking and alcohol consumption must also be evaluated.
Physical examination. It is essential to record the weight and height in order to calculate the BMI, and to measure the waist circumference and the blood pressure levels. The physical examination also helps to rule out other diseases such as, for example, the presence of reddish stretch marks (Cushing) or swelling (oedema) of the lower limbs (heart failure).
Blood analysis and imaging tests. They depend on the symptoms that the patient may have at the time, as well as the risk factors for developing other diseases. The blood tests consist of measuring fasting glucose levels, and cholesterol, as well as liver, kidney, and thyroid function, among others. It is also recommended to perform an electrocardiogram and a liver ultrasound in order to rule out hepatic steatosis (fatty liver disease).