& Joannie Dobbs Wednesday,
Switch from fat phobia to fat
In our Sept. 16 column, we talked about problems with using percentage of calories from fat as a way to determine if you are getting the right amount of fat in your diet. So, what can you use?
Counting grams of fat in your diet is an easy and practical method of monitoring your dietary fat. After all, grams of fat are listed on “Nutrition Facts” panels of food labels.
Here's an easy rule of thumb for most people – try to limit fat intake to around 50 grams per day. And for some people with preexisting problems related to cardiovascular disease, there are good arguments to keep fat as low as 30 grams per day.
Just as there are concerns for getting too much fat in the diet, there are concerns for getting too little fat, as well. Make no mistake, your body needs some fat in the diet. Fat assists the absorption of important fat soluble vitamins. Also, fat contains components called fatty acids, some of which are essential for health. It is better to become “fat smart” rather than “fat phobic.”
Most of us relate to the “scare” stories about high-fat diets and the increased risks of heart disease as a “distant future” problem. The fact is that research in the 1950s and today show that there can be almost immediate negative effects from single high-fat meals.
Almost half a century ago, Dr. Roy Swank (now at the Oregon Health Sciences University ) published several studies showing that after a single high-fat meal, blood becomes more viscous or sticky and blood flow through capillaries slows down considerably. This effect lasts for several hours after the meal.
Swank also fed stroke patients diets that contained 35 grams of fat per day for over a year. He reported a consistent decline in blood viscosity which would be expected to significantly reduce the risk of getting additional strokes.
More recently, Dr. Robert Vogel, Head of Cardiology at the University of Maryland School of Medicine, set out to demonstrate that a single high-fat meal was not a problem if your blood cholesterol was low. He used an ultra-sound technique to compare artery blood flow after a low-fat meal with a meal containing about 50 grams of fat. The results are startling.
Vogel found that the arteries narrowed significantly and blood flow slowed considerably for several hours only after the high-fat meal. This would put people already at risk for a heart attack at an even greater risk.
Vogel's comments after reviewing the results of the study, were, “You need to keep fat out of the diet each and every meal.”
If you think of your arteries like a highway, a high-fat meal is like closing off a lane on H-1 during rush hour. Add this fat to additional risk factors (highway detours), like stress, high blood pressure, diabetes, and smoking, and we don't really know what's going to happen. But other risks could cause gridlock.
Even adding the effects of exercise within 6 or 8 hours of eating a high-fat meal could cause problems. If arteries are narrowing and blood cells are more sticky, then the increased speed of blood flow from exercise could increase the risk of a heart attack.
Is 50 grams of fat a lot? Not in today's culinary arena, but you be the judge. Here are the some common foods and their fat content:
A tablespoon of oil (14 grams fat)
A package of dried ramen noodles (about 16 grams fat)
A typical fried pupu (about 30 grams fat)
A stir-fry serving (30-60 grams fat)
Some plate lunches (up to 150 grams fat)
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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