Diet pills are generally prescribed to treat obesity and should be used only under the strict supervision of a physician. For adults, obesity is defined as having a body mass index (BMI) above 30. However, the National Institutes of Health recommend that overweight adults with a BMI over 27 who also have obesity-related conditions (e.g., high blood pressure, type 2 diabetes) may benefit from diet pills. Diet pills should always be used in conjunction with a healthy diet and regular exercise.

Diet pills are not used to treat diabetes. However, weight control is an important aspect of managing diabetes and prediabetes. Diet pills may be recommended by a physician to reduce complications that may arise in people who have prediabetes or diabetes and are also overweight. Some of these complications may include:

• Hyperglycemia
• High blood pressure
• High cholesterol
• Heart disease
• Insulin resistance, which in people with type 1 diabetes can cause double diabetes
• Hyperinsulinemia
• Metabolic syndrome

Patients, especially those with diabetes, should consult their physician before taking diet pills, whether the drugs are prescribed or over-the-counter. Diet pills can affect the amount of insulin required by the body, which may result in higher dosages being needed. They may also affect glucose levels and cover up symptoms of hypoglycemia, which is of particular concern for people who have hypoglycemia unawareness (difficulty sensing low blood sugar).

In addition, diet pills may exacerbate many of the conditions that people with diabetes or other endocrine disorders are at risk for. These may include:

• High blood pressure
• Cardiovascular disease or heart attack
• Stroke and transient ischemic attack (mini-stroke)
• Kidney or liver problems
• Thyroid conditions, including hypothyroidism and hyperthyroidism
• Glaucoma

Additional conditions of concern with diet pills include:

• Depression, bipolar disorder or other emotional disorders
• Abuse of alcohol or drugs
• Seizure disorders