I have heard that, no matter how much food I eat, it is difficult to put on weight if I eat a very low-fat diet. Is this correct? 

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.

Despite decades of research, we still don't fully understand why some people gain weight more easily than others. It is known that body fat levels are increasing in Australia (along with most of the rest of the developed world). In 1995, 64% of men and 47% of women in Australia were overweight or obese (with no sign of a slowing in the rate of increase in obesity). Clearly, something is wrong with our diet and/or lifestyle.

There is currently much debate about the causes of this increase in body fat. It appears that both diet and lifestyle (particularly physical activity - or rather a lack of activity) are involved in what is being increasingly seen as an "epidemic of obesity", but the exact causes are still unresolved. 

Two major schools of thought exist on the importance of diet and obesity: 

1. For some years now the emphasis has been on reducing fat intake and increasing the intake of carbohydrate foods, particularly breads and cereals (preferably whole grain), vegetables (including legumes) and fruits. High carbohydrate intake may be protective in at least two ways: First, carbohydrate provides less than half the energy (kilojoules) per gram that fat provides. Second, carbohydrate foods such as breads, cereals, fruits and vegetables are rich in dietary fibre. High fibre intake should assist by causing a feeling of 'fullness' in the stomach for relatively little energy intake, so energy intake may be self-limiting. 
2. There is a new school of thought emerging. Some nutritionists favour a 'medium fat', but low saturated fat diet, with monounsaturated fat replacing much of the saturated fat. An additional advantage of this approach is the probable beneficial effect on heart health of reducing saturated fat intake. 

Regardless of the ultimate outcome of the debate between the 'low fat' and 'moderate, but modified fat' schools of thought, there is a consensus that avoiding high energy intakes is critical to weight control. That is, you will inevitably gain weight if your energy intake exceeds your energy output. 

Although reducing your fat intake may be helpful in weight control, it is not sufficient of itself - you must still ensure that your level of physical activity takes your energy expenditure above your energy intake. The importance of physical activity cannot be overemphasised, not only in weight control but for general health and fitness as well. Perhaps the best advice that can be given now is to follow the dietary guidelines, especially guidelines 3 and 4:

3. Eat a diet low in fat and, in particular, low in saturated fat.

4. Maintain a healthy body weight by balancing physical activity and food intake.

 

For more information Nutrition Australia recommends:

• Eating Activity, Sport and You

Back to Frequently Asked Questions Index

[Date issued: June 1999]

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.