Wednesday, June 2, 2010

Change your Oil: Fats and Cholesterol

"Eat a low-fat, low-cholesterol diet" has been the mantra for healthful eating for decades. The low-fat approach to eating may have made a difference for the occasional individual, but as a nation it hasn't helped us control weight or become healthier. I am seeing a larger number (even very thin) patients with high cholesterol and triglycerides.  Why hasn't cutting fat from the diet paid off as expected? Detailed research—much of it done at Harvard—shows that the total amount of fat in the diet isn't really linked with weight or disease.

What really matters is the type of fat in the diet.
Bad fats, meaning saturated fats, increase the risk for certain diseases.
Very bad fats, meaning trans fats,  are worse for cholesterol levels than saturated fats because they raise bad LDL and lower good HDL.
Good fats, meaning monounsaturated and polyunsaturated fats, do just the opposite. They are good for the heart and most other parts of the body. There is no good evidence that replacing saturated fat with carbohydrates will protect you against heart disease, while there is solid proof that replacing saturated fat with unsaturated fats will help. Here are three helpful tips:

1. Try to eliminate trans fats from partially hydrogenated oils. Check food labels for trans fats; avoid fried fast foods.

2. Limit your intake of saturated fats by cutting back on red meat and full-fat dairy foods. Try replacing red meat with beans, nuts, poultry, and fish whenever possible, and switching from whole milk and other full-fat dairy foods to lower fat versions.

3. In place of butter, use liquid vegetable oils rich in polyunsaturated and monounsaturated fats in cooking and at the table such as canola and olive oil.

My patients often ask, "How much fat should I eat per day"?
  • It generally is figured as a percentage of your daily caloric intake, which varies with your age, sex, and activity level.
  • The American Heart Association recommends limiting dietary fat to 30% of total calories, however, if you are overweight, need to lower blood cholesterol or have another medical concern, you may need less than the recommended 30%. Back to the math: for 1,600 calories diet - Limit fat to 50 grams.
  • The Dietary Guidelines for Americans recommend no more than 10 percent of your total daily calories come from saturated fat (for a 2,000-calorie diet this would be about 20 grams per day), and your trans fat consumption should be as low as possible.