ST Feb 15, 2006
Is this back on the menu?
Supporters of low-carb, high-fat diets gloated last week as doctors scrambled to contain the damage of a huge and expensive study which set out to show the benefits of a low-fat diet - and couldn't.
The study involved nearly 49,000 women aged 50 to 79 who were followed for eight years. Those on a low-fat diet were found to have the same rates of breast cancer, colon cancer, heart attacks and strokes as those who ate whatever they pleased.
Hurray! said everyone else, while doctors hurried to come out in support of low-fat diets anyway. Even if the largest study ever done on the subject showed that it didn't cut the risk of heart disease and cancer, they were sticking by the mantra that low fat was good for the heart.
The thing about these studies is how contradictory they can sound. One day, you're told to eat margarine; the next day, you find out that butter is better. One day, you're loading up on fibre; the next, some surgeon says the way to cure constipation is to go slow on the greens.
What's one to make of these mixed signals?
Mr Wang is neither a doctor nor a nutritionist. So he may not be very qualified to comment on this topic. However, from a layman's commonsensical point of view, Mr Wang feels that this study on low-fat diets and their effect on the risk of major diseases may be missing a rather important point.
In Mr Wang's mind, the reason for being on a low-fat diet is so as not to be fat. The reason for not being fat is that you become less likely to get cancer, heart disease etc. However, being on a low-fat diet may or may not succeed in making you thin.
For example, if you're on a low-fat diet but you consume huge quantities of low-fat food (for example, lots of rice and bread every day), you could still be very fat. Conversely, you might not be on a low-fat diet but if you exercise a lot (run, swim, cycle etc), you may still be quite slim.
The study did not seem to have focused on whether the women on low-fat diets were indeed thinner than the women who ate whatever they pleased. The scientific conclusion was merely:
Women on a low-fat diet were found to have the same rates of breast cancer, colon cancer, heart attacks and strokes as those who ate whatever they pleased.This is NOT the same as saying:
Women who were thin were found to have the same rates of breast cancer, colon cancer, heart attacks and strokes as those who were fat.Who knows? Perhaps the truth is simply that if you're thin, you can eat whatever you like. And if you're fat, you ought to lose some fat. Oh, and that just going on a low-fat diet may not be an effective way to do that.