Will Low-Carb Diets Ultimately Make Us Fat?
Many low-carb diets emphasize eating only "good" carbs from fruits, vegetables, and whole grains, but supermarkets are being flooded with low-carb junk food.
Friend or Fad? continued...
Wiant points to several short-term studies that show the
benefits of low-carb diets: quick weight loss and improved cholesterol levels.
To counter the naysayers, he says there have been long-term studies (12 months
long) of the diet that demonstrate sustained weight loss without increasing
their risk of heart disease.
Yet Kantor expects research to someday catch up with the ills
of low-carb diets. "In the long term, there is no question that low-carb
diets will be shown to be dangerous," he says, noting that hundreds of
epidemiological studies around the world have demonstrated that
high-carbohydrate foods such as fruits, vegetables, and whole grains reduce
risk of heart disease and prevent cancer.
Wiant responds in defense of low-carb diets. "It's
irresponsible to conclude, based on the data out there, that the long-term
studies will show some kind of huge reversal of [improved cholesterol]
numbers," he says.
At the heart of the food fights on what will sustain weight
loss and lower heart disease risk is the indisputable fact that American waist
sizes are expanding.
According to the National Center for Health Statistics, 64% of
adults aged 20 years and older are overweight or obese, a 20% jump from the
early 1960s. In preteens and teenagers, the numbers of overweight are both at
15%, compared with about 4% each 40 years ago.
The figures are especially alarming given that risks of
developing diabetes and heart disease increase with weight.
Experts blame a sedentary lifestyle and bigger food portion
sizes for the bulge. But there is also some finger pointing at the role of
processed foods and junk food such as white breads, white rice, pasta, soda,
chips, and cookies.
Wiant says many of the low-fat products caused weight gain
because manufacturers added carbohydrates to the food to make up for the lack
Low-carb critics could apparently make the same argument. In
order to replace carbohydrates, food makers have had to add fat, protein,
fiber, water, or sugar-free sweeteners.
"You can't have a low-fat, low-carbohydrate, low-protein
food, because then, what have you got?" says George Bray, MD, Boyd
Professor in the division of nutrition and chronic diseases at the Pennington
Biomedical Research Center in the Louisiana State University system.
"Whenever someone lowers something, there's been a relative replacement by