A body-fat level above the safe percentage can increase the risk for many health conditions. If excess fat is mainly visceral (that is, internal organs compared to subcutaneous), it can lead to medical conditions such as heart disease, diabetes, cancer and so on.

We live in a society where the general population is increasing in average body mass index (BMI) and this condition destroys self-esteem in many individuals and even increases social stigmatisation. The quest to reduce body fat has become a booming multibillion-dollar industry. Documented success, however, is not as overwhelming as the industry's financial worth.

A look at current scientific evidence and clinical guidelines shows the following:

Diet alone

Calorie restriction, used to reduce body fat, and various combinations of food groups and nutrients, have been used successfully. The real issues are the duration of the achieved weight loss and health consequences. Some of the never-ending list of calorie-restrictive diets include low carbohydrate, low fat, vegetarian and Mediterranean.

The results of many randomised controlled trials indicate strong and consistent evidence that a low-calorie diet (LCD) between 1,000 and 1,200 calories can achieve an eight per cent weight loss, including abdominal fat, in overweight and obese individuals over a three- to 12-month period. The evidence also shows that when reduced fat is a part of this low - calorie regime, the weight loss can be greater. The evidence shows that a very low-calorie diet (VLCD) will result in greater weight loss initially, but there is no increase over LCD in one year. It is harder to observe a VLCD long term.

The evidence shows that reducing fat alone will not facilitate weight loss, but reduced fat and carbohydrate will, as a part of an LCD. The evidence and guidelines also state that diets which are individually planned to help create a deficit of 500 to 1,000 calories per day, should be an integral part of a weight- loss programme.

Exercise alone

The evidence shows that aerobic activity done three to seven times weekly in 30-minute sessions can result in modest weight loss, independent of diet.

Diet and exercise

The combination of a reduced-calorie diet and increased physical activity is recommended since it produces weight loss greater than diet alone. This will result in reduced abdominal fat and improved cardiorespiratory fitness.

Behaviour therapy

No one behaviour therapy appears superior. When used in addition to a low- calorie diet and increased physical activity, behaviour therapy will result in weight loss for up to one year. No improvement is seen after one year unless therapy continues.

Pharmacology

Weight-loss drugs approved by the US Food and Drug Administration for long-term use may be used as part of a comprehensive diet and exercise programme. It is indicated for patients with a BMI equal or greater than 30 with no concomitant obesity-related risk factors or disease or in persons with a BMI equal or greater than 27 with concomitant obesity-related risk factors or disease. There are two drugs approved for long-term use - one is an appetite suppressant and the other a lipase inhibitor, which prevents fat breakdown and absorption.

Bariatric surgery

This method is the most successful to date in percentage weight loss seen in patients (up to 90 pounds in one year) but is only recommended for patients with clinically severe obesity with a BMI equal or greater than 40, or equal or greater than 35 with co-morbid conditions. These patients are carefully selected based on their morbidity and mortality risks.

These guidelines may need adjustment in the elderly or in specific disease states and ethnic groups. Individual consultation with a medical professional, who will carry out specific assessment and recommendation, is strongly advised.

Rosalee M. Brown is a registered dietitian/nutritionist who operates Integrated Nutrition and Health Services; email: yourhealth@gleanerjm.com.