Dramatic cutbacks in one's daily intake of dietary fat can actually undermine overall health, experts say. They recommend more moderate low-fat diets as a means of bringing blood cholesterol under control. Aggressive fat restriction offers no (health) benefit beyond that achieved with moderate restriction and may, in fact, be counterproductive.
In a study, subjects were placed on one of four different types of year-long, low-fat diets. The diets, simply labeled Diets 1, 2, 3, and 4, were constructed so that the overall daily energy obtained from dietary fat equaled 30%, 26%, 22%, and 18%, respectively. Tests conducted one year into the diets revealed that those men with both high-cholesterol and high-triglyceride levels saw their levels of LDL drop most dramatically with Diet 1, the least restrictive of the four regimens. Diets 2, 3, and 4 -- each with much tighter limits on fat intake than Diet 1 -- were found to be "without added benefit" in terms of cholesterol reductions, the researchers say.
Furthermore, no statistically significant added benefit of more aggressive fat restriction beyond Diet 1 was observed in body weight, glucose (blood sugar), insulin, or blood pressure levels in the subjects under study. In fact, they believe diets which demand severe cutbacks in daily fat intake could actually be "counterproductive" to health. The investigators point out that blood tests on men enrolled in Diets 3 and 4 revealed a rise in triglyceride levels, along with a drop in levels of healthy HDL, or "good," cholesterol.
Journal of the American Medical Association (1997;278(18):1509-1515)
COMMENT: This study shows very clearly the fallacy of the "Low Fat Myth" that our culture is infatuated with. When you decrease your fat levels below 30% you have to replace it with something. There are only two other options, protein or carbohydrates. Most people will select the carbohydrates, such as bread, pasta, cereals, rice, potatoes, fruits or starchy vegetables. These items will raise insulin levels and decrease HDL levels, and raise triglyceride levels, both of which are potent predictors of heart disease as reviewed in a previous newsletter.
So, the take home message is you should strive for 30% of each meal to be fat. The fat should be good such as olive oil, seeds or nuts. Try to avoid canola oil, as although it is high in monounsaturates it has not been around for more than ten years and is highly processed. Dr. Enig from the University of Maryland who is the major researcher in the world on trans fat, has strong feelings that this oil was not really designed for human consumption. Organic eggs, about one dozen per week, would also be good as long as one was not allergic to them and did not eat them every day.