Obesity
(Overweight · Unhealthy Weight)
In this condition factsheet:
Diagnosing Obesity
The diagnosis of obesity is usually based on a physical examination and a patient history (i.e., eating and exercise habits).
A measurement called the body mass index (BMI) does not directly measure body fat, but it is a useful tool to assess the health risk associated with being overweight or obese. A BMI of 18.5 to 24.9 is considered within the healthy range. The BMI is calculated using kilograms (kg) and metres (m) instead of pounds (lb) and inches/feet. Keep in mind that 1 lb equals 0.45 kg and 1 inch equals 0.0254 m.
BMI is calculated as follows:
BMI = body weight (kg) ÷ height² (m)
Example: if you weigh 150 lbs (68 kg) and are 5'8" (1.73 m) tall, divide 68 by (1.73 × 1.73), or 2.99. The result is 22.74, which is right in the middle of the healthy range.
Obesity Canada classifies BMI according to the associated risk of developing health problems:
Caucasian, European, and North American ethnicity:
BMI value |
Classification* |
Less than 18.5 |
Underweight |
18.5 to 24.9 |
Normal weight |
25.0 to 29.9 |
Overweight |
30.0 to 34.9 |
Obese class I |
35.0 to 39.9 |
Obese class II |
40.0 to 49.9 |
Obese class III |
50.0 to 59.9 |
Obese class IV |
60 or higher |
Obese class V |
South, Southeast, or East Asian ethnicity:
BMI value |
Classification* |
Less than 18.5 |
Underweight |
18.5 to 22.9 |
Normal weight |
23.0 to 24.9 |
Overweight – at risk |
25.0 to 29.9 |
Overweight – moderate risk |
30 or higher |
Overweight – severe risk |
*The above classification does not apply to people younger than 18 years of age, pregnant women, or breast-feeding women. For people 65 years and older, the "normal" range is higher, beginning slightly above 18.5 and extending into the "overweight" range.
Doctors may also use other measurements, such as waist size, to evaluate health risks associated with excess abdominal fat. When BMI and waist size indicate a high risk for health problems, additional tests may also be performed.
Treating and Preventing Obesity
Changing your lifestyle
Obesity is managed and treated to decrease the health risks caused by obesity and to improve quality of life. An appropriate weight management program usually combines physical activity, healthy diet, and change in daily habits. Other programs may also involve psychological counselling and, in some cases, drug therapy. Losing weight and keeping it off is very challenging because lifestyle and behavioural changes are required.
What's important is to eat a healthy, balanced diet. Fad and crash diets don't work and can be dangerous. The body needs a minimum amount of energy from food to function normally. No daily diet with less than 1,200 calories should be used without medical supervision. "Crash diets" are never successful in the long term because once the diet is stopped, the weight usually comes back. Additionally, such diets may be associated with a host of nutritional deficiencies and imbalances that could endanger your health. Commercial weight-loss plans and clinics are successful businesses because they have so many return customers.
To lose weight successfully, and to maintain a healthy weight, requires lifelong changes in eating and exercise habits as well as an understanding of emotional factors that lead to overeating. It also involves setting and achieving specific and realistic goals. People who are medically obese should consult a doctor or dietitian for a safe and personalized weight-loss program. Behavioural therapy or modification can also help. Seeing a therapist or counsellor can help you understand the emotional and psychological reasons for overeating and can teach you ways to manage your eating triggers.
Regular physical activity is an important part of weight management. In addition to managing weight, exercise also improves overall health and can help reduce the risk of diseases such as certain cancers, heart disease, and osteoporosis. Regular physical activity doesn't mean you have to join the nearest gym. It can be as simple as climbing the stairs instead of taking the elevator, walking or cycling to work and leaving the car at home (if at all possible), or going for a walk at lunchtime with coworkers. What's important is to add exercise to your daily routine, and to work towards a higher activity level. Choose activities and exercises you enjoy.
Medical intervention
Medications may be part of a weight management program. Medications aren't "magic cures" leading to permanent weight loss. They're generally used in combination with a proper diet and exercise program. They are only for people who are classified as obese (i.e., those with a BMI over 30), or people with a BMI of 27 and extra heart disease risk factors such as high cholesterol or diabetes.
Some medications are approved for short-term use only. One example of a weight-loss medication available in Canada is orlistat*, which blocks the absorption of fat from the bowel. Glucagon-like peptide 1 (GLP-1) analogs, medications used traditionally in managing diabetes with appetite-suppressing effects, may also be used for weight loss. GLP-1 analogs that have been studied to treat obesity include liraglutide and semaglutide.
A combination of naltrexone and bupropion may be used to help with weight loss. Naltrexone is thought to help by suppressing appetite, while bupropion (traditionally used as an antidepressant) changes the amount of certain chemicals in the brain which causes a reduction in food intake. Talk to your doctor about whether medications are an option for you.
Surgery is only considered when other weight management options have not been successful. There are many forms of obesity surgery, but often surgery reduces the size of the stomach so that only a small amount of food can be eaten comfortably. Some of the terms used to describe the surgeries used to treat obesity include:
- adjustable gastric banding
- duodenal switching
- gastric bypass surgery
- gastric sleeve surgery
- laparoscopic gastric banding
- Roux-en-Y gastric bypass
- sleeve gastrectomy
- stomach "stapling"
- vertical sleeve gastrectomy
When reviewing suitable management options, it's important to consider the risks and benefits of each option. Your doctor and other health care professionals can provide you with the information you need to make an informed choice about what options are best for you.
*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.
All material copyright MediResource Inc. 1996 – 2024. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source: www.medbroadcast.com/condition/getcondition/Obesity
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