Summary of FAQ about overweight/ obesity and the role of activity in weight maintenance and weight loss

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.
[Note: This series of questions/answers addresses the definitions and likely causes of overweight/obesity, and the place of activity in relation to weight maintenance and weight loss. Other, related FAQs in this series discuss Activity for General Health, Activity for Physical Fitness, and the difficulty many people have in losing weight.] Date of last revision: March 2004.

In the past 20 years or so the proportion of Australian adults who are obese has more than doubled. Although a small amount of excess body fat (i.e., being only slightly overweight) is not likely to be very harmful to health for most people, being obese significantly increases the risks of a wide range of diseases, including heart disease, diabetes, stroke, osteoarthritis and gallbladder disease. This is especially true for people who have excess ‘abdominal’ fat (e.g., the so-called ‘beer gut’ that is developed by many Australian men).

The causes of this increase in body fat levels are not completely understood, but it is known that genetic differences between people make it very easy for some individuals to maintain normal weight, while others must struggle mightily to keep their weight down.

Diet clearly plays a part—for example, high-fat foods (particularly those high in saturated fat such as fatty meats, sausages, cream-based foods, cakes, pastries and many takeaway foods) promote the storage of body fat, while high-fibre foods promote a feeling of fullness for relatively low kilojoule intake, and therefore help to protect against overeating. The best sources of fibre are breads and other cereal foods (preferably wholegrain), vegetables and fruits.

Another problem is that most people are less active than their parents/ grandparents were. It is now generally believed that both diet and activity levels are vitally important in maintaining (or regaining) appropriate body weight.

But the belief is that exercise (i.e., structured, planned physical activity), while important, is not the only way in which activity might help protect against obesity. Rather, movement or incidental physical activity that we do almost unconsciously through the day is now believed to be very important in adding to our energy output and therefore helping to keep our weight at an appropriate level.

In summary, for people who are not overweight/obese, the National Physical Activity Guidelines for Australians are:

• Think of movement as an opportunity, not an inconvenience
• Be active every day in as many ways as you can
• Put together at least 30 minutes of moderate intensity physical activity on most, if not all days of the week
• If you can, also enjoy some regular vigorous exercise for extra health and fitness

For people who need to lose some body fat, the intensity of activity may need to be greater than for simply maintaining weight. Of course, if you are well above your ‘best fighting weight’ it will be difficult to exercise vigorously at first. The exercise program you develop (preferably with a qualified person such as an exercise physiologist or fitness trainer) should allow you to start gradually and slowly build up both the duration and intensity of exercise.

Many people also find that taking ‘time out’ from a busy day by going for a stroll in the park, playing tennis, chopping firewood, taking the dog for a walk or digging over the vegetable garden (as just a few examples) is effective in reducing tension and helping to reduce stress-induced overeating. Exercise has even been successfully used in the treatment of mild depression

Weight should only be lost slowly: about one-half to one kilogram per month is fast enough. Some key steps in weight reduction are therefore:

1. A slight reduction in total food intake;
2. A major reduction in intake of fatty foods, especially those high in saturated fat;
3. Increased incidental physical activity; and
4. Commencing a program of structured physical activity that involves gradually increasing both volume and intensity of exercise.

The most important thing is to achieve a weight and body shape that is healthy for you as an individual, and that can be maintained. Healthy behaviours (increased activity, lower fat diet, limiting alcohol consumption, reducing stress, quitting smoking) will all contribute to achieving this aim, and, if you persevere, to some weight loss as well.

View the detailed FAQ on activity and overweight.

Back to Frequently Asked Questions Index

Disclaimer: This material is provided on the basis that it constitutes advice of a general nature only. It is not intended to replace the advice of a physician or a dietitian.