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Slim effortlessly: use olive oil instead of butter
Want to reduce your fat percentage? According to researchers at Menzies School of Health Research, you have more nutritional tools at your disposal than you perhaps realise. Changing the kind of fat you eat is one way. Replace butter and cheap cooking margarines with olive oil, cheese and dairy fats with nuts – and you'll lose weight without even noticing.
The effect of foods containing saturated fats is therefore neutral, as far as heart and blood vessels go, while the effect of most natural foods containing unsaturated fatty acids is positive – in healthy people at least.
Saturated fatty acids are found above all in industrially processed foods, and in dairy and meat. That's why producers of these products are happy to finance research that shows that nutritionists have got the wrong end of the stick. Wageningen University in the Netherlands recently produced such a study, and promoted it in a misleading way, which led to quite a scandal. [sciencemag.org 20 October 2011]
Unsaturated fatty acids are found in olive oil, nuts, seeds and fish. Olive oil and avocado contain relatively high amounts of mono-unsaturated fatty acids; sunflower oil and fish contain relatively high amounts of poly-unsaturated fatty acids; nuts contain both.
The industrial lobby is losing ground. Over the last fifteen years nutritionists have been examining a new aspect of fatty acids: their influence on metabolism. This research also indicates that a diet that is high in unsaturated fatty acids is better for us. Studies suggest that, the more the fats in the food are unsaturated, the more energy the body burns. That's not surprising: the structure of unsaturated fatty acids means they are easier to convert into energy than most saturated fatty acids are.
In 2003, for example, Australian nutritionists published the results of an experiment they had done on 8 fat male subjects aged between 24 and 49. The researchers put the men on a diet twice. For both diets the men were allowed to eat as much as they wanted. The only difference between the two diets was the fatty acid composition.
On one diet the men ate foods containing predominantly saturated fatty acids [SFA]. Their energy was derived for 24 percent from saturated fats, for 13 percent from mono-unsaturated fats and for 3 percent from polyunsaturated fats.
The other time round them men ate foods containing predominantly mono-unsaturated fatty acids [MUFA]. Their energy was derived for 11 percent from saturated fats, for 22 percent from mono-unsaturated fats and for 7 percent from polyunsaturated fats.
The table below shows that the saturated fatty acids in the SFA diet were derived mainly from dairy fat, in the form of cheese, butter and whole milk. In the MUFA diet they were derived mainly from olive oil and nuts.
The figure below shows that the men on the MUFA diet lost weight without losing fat mass – and that happened without the men eating less. The fatty acid composition did not influence the amount of calories the men ate.
"Substituting dietary saturated with unsaturated fat, predominantly MUFA, can induce a small but significant loss of body weight and fat mass without a significant change in total energy or fat intake", the researchers conclude. On the basis of other studies, they suspect that a diet rich in mono-unsaturated fatty acids contributes to an increase in fat burning.