Is Fat Making a Comeback?
Not really. But experts say low-fat diets aren't the answer.
May 15, 2000 -- Don't butter your bread. Try marinara sauce instead of
alfredo. Go easy on fried foods. We Americans have heard it all. And
nutritionists' goading has worked. We've cut back on fat -- from 40% of
calories in 1968 to only 33% today. We've also lessened the amount of saturated
fat in our diets from 18% to only 11%, according to the U.S. Department of
Agriculture. By all rights, we should be throwing a party for ourselves,
complete with low-fat chips and a piece of fat-free cake for everyone.
But just when it seems like it's time to break out the noisemakers,
naysayers have crashed the party, warning that low-fat diets aren't a good idea
for everyone. Some of the country's leading diet and health experts, in fact,
now say that a low-fat, high-carbohydrate diet -- precisely the diet
recommended by the American Heart Association -- could actually increase your
risk of getting coronary heart disease rather than decrease it.
The Lowdown on Low-Fat Diets
It's easy to understand why experts might have first begun recommending
low-fat, high-carbohydrate diets. Gram for gram, fat contains more than twice
the number of calories as carbohydrates. Cutting back on the amount of total
fat in the diet and replacing it with carbs would seem to be a great way to
Fat, in its saturated form, can also raise cholesterol in the blood, which
increases your risk for heart disease. "Cut back on total fat, the thinking
went, and you'll cut back on saturated fat," says Marion Nestle, PhD, head
of New York University's food sciences department.
But cutting back on fat hasn't worked as well as was first hoped when it
comes to helping us lose weight. While products like low-fat crackers and
nonfat cakes have crowded grocery store shelves, Americans have continued
getting fatter and fatter. The reason: Although we're eating less fat, we're
consuming even more calories than ever, feasting on sugars and highly refined
flour -- otherwise known as simple carbohydrates.
It's not just looking sexy in a bathing suit that's at stake, either.
There's another, more serious reason to question the merits of a low-fat,
high-carb diet: While such an approach reduces artery-clogging LDL cholesterol,
the low-fat, high-carb diet also lowers another form of cholesterol known as
HDL. Sometimes called "good" cholesterol, HDL has been shown to remove
"bad" LDL cholesterol from the bloodstream.
"When HDL levels fall, heart disease risk climbs, even if your total
cholesterol remains normal," says Frank Sacks, MD, a leading epidemiologist
at the Harvard School of Public Health. A low-fat, high-carbohydrate diet also
raises the level of triglycerides -- fat molecules in the bloodstream that are
a marker for increased heart disease risk.
A far healthier diet, Sacks and others believe, is one rich in unsaturated
fats, which are found in vegetable oils, nuts, seeds, and grains. On a
relatively high-fat diet -- as long as the fats are unsaturated -- levels of
bad cholesterol fall while levels of good cholesterol remain high, studies
show. Triglycerides also stay low. Sacks, who is also a heart specialist,
believes a heart-healthy diet can contain up to 40% of its calories from fat,
as long as most of the fat is unsaturated.