Balancing the Evidence: What is right for you?
Introduction
What is Dietary Fat?
Cancer and Dietary Fat
Heart Disease and Dietary Fat
Obesity and Dietary Fat
What is Right for You?
About This Site
All of the evidence in the medical literature supports the fact that being overweight increases the risk of heart disease, cancer and other chronic diseases. The single most important change that an individual can make to improve his/ her health is to obtain and maintain a healthy weight. In order to lose weight most people need to establish a plan that includes regular physical activity and dietary modification.

There is little evidence to support the use of a low carbohydrate diet for weight reduction. Most of the research studies show that people who consume a low fat diet have a lower risk for being obese and if they have lost weight they are better able to maintain the lower weight on a low fat diet. In order to lose weight the amount of kilocalories consumed must be less the amount that are used.

So what about all the people who claim they have lost many pounds on high fat low carbohydrate diets? Very few studies that examine this question have been published. Recently two prospective but uncontrolled studies published in abstract form suggest that restriction of carbohydrates with unrestricted intake of fat and protein causes a voluntary decrease in total energy intake by about 1000 kcal per day. These studies should be interpreted cautiously, but a decrease in total energy intake of 1000 kcal/day will always result in weight loss. So perhaps increasing the fat content of the diet will make it easier for some people to restrict their caloric intake and lose weight.

Can you increase the fat in your diet and still have a healthy diet? The research suggests that this is not likely if most of your high fat foods are animal foods. If you want to increase the fat in your diet, the fat should come from vegetable oils that are good sources of monounsaturated fats, like olive and canola oil and nuts, seeds and fatty fish. Care should be taken not to eliminate fiber rich, minimally processed fruits, vegetables and grains because their potential to reduce the risk of cancer.

Foods that meet these requirements are not as easy to obtain as high fat, fast food but finding them and using them in your diet may have long term benefits for weight loss and health.

Dietary Recommendations: The best diet to decrease the risk of chronic disease including heart disease cancer and obesity should have about 30% of the kcal from fat. Most of the fat should be monounsaturated or poly saturated including omega 3 fatty acids. Trans fat should be avoided and saturated fats limited. A wide variety of fiber rich, minimally processed fruits, vegetables and grains should make up the remainder of the diet.

Some people may find it easier to reduce their caloric intake if the diet is slightly higher in fat. There should be little risk in increasing the fat content to about 40% of the kcal as long as the recommendations about the type of fat are followed. The Mediterranean Diet would be consistent with this recommendation.

The USDA Food Pyramid is a useful resource for converting these recommendation into food choices. This article, Are All Food Pyramids Created Equal?, contains several versions of the pyramid that can be used to plan a healthy diet.

References from the Medical Literature:

  1. Grundy, SM. The optimal ratio of fat to carbohydrate in the diet. Ann Rev Nutr. 19:325-41.
    • Strong evidence supports the need to reduce the intake of saturated and trans fatty acids in the diet. [abstract]
  2. Klein, S. Medical Management of Obesity. Surg Clin North Amer. 81:1025-38, 2001
    • Review of non-surgical approaches for weight loss in obese patients. [abstract]
  3. Shikany, JM; White, GL Jr. Dietary guidelines for chronic disease prevention. S Med J. 93:1138-51, 2000.
    • Intake of monounsaturated fats, fiber, calcium vegetables, fruits and whole grains should be promoted. Consumption of saturated and trans fats, sodium and refined grains should be minimized. [abstract]
Link to introduction page

10/21/02