In 2004, about one in four (23 per cent) adult Canadians were obese, while 59 per cent were overweight. Obesity affects not just adults, but children too. One in four Canadian children and teens aged two to 17 were overweight. Obese children tend to grow to be obese adults.

Obesity is not so much a cosmetic or body image issue, but a health concern. It is a key risk factor in a number of diseases. If you are overweight, you are more at risk of health problems compared to someone with a healthy weight. Such health problems include diabetes, high blood pressure, high cholesterol, heart disease, stroke, osteoarthritis and certain types of cancers.

Measuring obesity

Overweight and obesity can be defined as carrying excess fat that harms health. The Body Mass Index (BMI) and waist to hip ratio are the two most commonly used methods of predicting the health risks of obesity.

The body mass index (BMI) reflects total body fat and can decide if someone is overweight. It considers weight in relation to height. It is calculated by taking weight in kilograms and dividing it by the square of the person’s height in metres (kg/m2). People with a BMI of 25 or more are considered overweight, while those at 30 or more are obese. The BMI indicates whether someone is at increased risk of certain health problems like diabetes and heart disease. However, it is not appropriate for growing children, muscular individuals, and pregnant women.

For most of us, carrying extra weight around the waist is more of a risk than weight on thighs and legs. Abdominal fat has been shown to contribute to heart disease risk. Body mass index does not measure abdominal fat. Measuring waist circumference or waist to hip ratio better predicts abdominal fat and disease risk.

For women, a waist circumference of more than 80 cm (31.5 inches) suggests a higher risk of diseases associated with being overweight. For men, it is a waist circumference of more than 94 cm (37 inches). For both men and women, having a larger waist than hips is considered in the danger zone for diseases such as heart disease. To find out how to check your BMI and properly measure your waist, visit Family Health OnLine, Use ‘BMI’ in a keyword search.

What causes obesity?

Obesity happens when more calories are consumed than the body burns. It is not simply eating too much or not doing enough exercise. A number of different factors are involved. Obesity is a complex medical problem with environmental, social and genetic factors. Recent evidence suggests that in some cases genetics may affect appetite and fat metabolism, leading to obesity.

Treating obesity with lifestyle changes - diet and exercise

Lifestyle changes are recommended for anyone who is overweight. Changes to diet, exercise and behaviour are key. Involving a health care team is the most effective approach.
According to evidence-based Canadian obesity clinical practice guidelines used by physicians, lifestyle changes play a role in preventing and managing obesity. The guidelines suggest reducing energy intake by 500 to 1000 calories a day. As well, shift from saturated to unsaturated fat and limit the amount. Cut down on sugar while eating more fruits and vegetables.

If you are obese, reducing your weight by five to 10 per cent can lower your risk of diabetes and heart disease. One pound (0.45 kilograms) is equal to 3500 calories. By reducing energy intake by this amount over a week or burning an extra 500 calories a day, you can lose about a pound a week.

As for physical activity, try 30 minutes of medium intensity activity three to five times per week to start. Eventually, increase to more than 60 minutes on most days. Endurance exercise training can be added under medical supervision.

Medical intervention – weight loss medications

In some cases, medications can encourage and maintain weight loss.

Two medications have been approved in Canada - Meridia™ (sibutramine) and Xenical™ (orlistat). They are not a magic bullet leading to permanent weight loss. They must be used in combination with an appropriate diet and exercise program. These two products are approved for long term use in Canada.

In the United States orlistat is available as Alii™, an over-the-counter (otc) medication. The medication rimonabant was voluntarily withdrawn worldwide by the manufacturer last fall and so is no longer available.

How do medications work?

Meridia™ affects appetite control centres in the brain. It is an appetite suppressant, lowering appetite or increasing the feeling of fullness so you do not feel as hungry.

Xenical™ works by decreasing the absorption of fat from the bowel. It blocks an enzyme called lipase. Lipase breaks down large fat molecules into smaller fat molecules, which are then absorbed by the body. When lipase is blocked, 30 per cent less dietary fat is absorbed into the gut or body. Fat that is not absorbed is eliminated in the stool.

Are weight loss medications safe and effective?

Weight loss medications modestly reduce weight, usually by slightly less than five kilograms per year. Even this modest weight loss improves associated metabolic problems. Regaining weight is common after stopping the medications.

Meridia™ can increase blood pressure and heart rate in some people. Headache, dry mouth and constipation are the most common side effects. Side effects of Xenical™ include cramping, diarrhea, gas, and leakage of oily stool. These are temporary effects that increase after eating fatty foods. Multivitamins should be spaced at least two hours from when Xenical™ is taken, as some vitamins will not be absorbed as well.

Human body weight is meticulously regulated by internal mechanisms, and that is why weight loss is modest in most cases. Even a modest weight loss of 5-10 per cent improves associated problems including high blood pressure, altered blood sugar levels, increased lipid levels and risk for diabetes and cardiovascular disease.

What about herbal products?

A number of herbal weight loss products are sold in pharmacies and herbal stores. Think carefully about whether a product is effective and safe to use. Many herbal supplements do not undergo the same drug testing standards as prescription and over-the-counter medications.

Weight loss products can contain a cocktail of ingredients. They may include various herbs, vitamins, minerals and other ingredients such as caffeine or laxatives. Common caffeinated ingredients include cocoa, coffee, guarana, kola nut, mate leaf and tea (black, green, and oolong). Weight loss ingredients may include bitter orange, conjugated linoleic acid, and chromium.

Most herbal products are not clinically effective for losing weight. Their long-term effects have not been studied. Bitter orange contains the stimulant synephrine. This may cause heart problems, especially when combined with caffeine. Conjugated linoleic acid may improve lean body weight, but does not help with weight loss. Chromium is not considered effective either. In high doses it may cause blood, kidney and liver disorders.

We do not know how such weight loss ingredients act individually or throughout the body. As well, the effect in combination with prescription medications is unknown and requires more study.

Ephedrine, a medication once used as an appetite suppressant, was removed from the market several years ago. It was linked to several deaths due to palpitations (irregular or forceful heart beat), high blood pressure, and heart attacks.

Remember, herbal products are still drugs. Closely read and question labels on herbals. To be certain, talk with your pharmacist or health care provider about any dietary supplement.

Obesity is a chronic medical condition that can seriously affect your health. Lifestyle changes, including diet and exercise, can make a big difference. For some, medical intervention, including the use of medications, may help. It must be emphasized that even a modest weight loss of five to ten per cent reaps huge health benefits. Talk to your doctor for more information.

Treating Obesity Is medication the answer?