Low Carb Out, Slow Carb In?
Researchers say people lose weight on a low-glycemic-load diet
May 11, 2005 -- They ate all they wanted, yet lost weight.
They didn't avoid fats or carbs. They didn't count calories or eat
prepackaged foods. Yet 11 obese 30-year-olds lost more weight than 12 of their
peers on a conventional low-fat diet. And they lowered their risk of heart
They didn't do it with a low-carb diet, but with a slow-carb diet.
It's what nutritionists call a low-glycemic-load or a low-glycemic-index diet.
The key is eating plenty of satisfying foods that your body can't quickly
convert into sugar -- slow carbs, as they're coming to be called.
And it seems to work, says David S. Ludwig, MD, PhD, associate professor of
pediatrics at Children's Hospital, Boston. Ludwig's small study appears in the
May 1 issue of the American Journal of Clinical Nutrition.
"A diet focused on glycemic index may be easier to follow than diets
restricted in either fat or carbs," Ludwig tells WebMD. "And there
seems to be an additional benefit in reducing the risk of chronic
Low-Glycemic Diet Made Simple
Foods have a higher or lower glycemic index (GI) depending on how much of
them you eat, how you cook them, and what you eat them with.
This can quickly get complicated -- especially as it's not always easy to
tell which foods are low-GI and which are high-GI. Ludwig's team came up with a
simple plan. They created a low-glycemic-load food pyramid:
- At the bottom -- the basis of the diet -- are fruits and vegetables, cooked
or served with healthful oils.
- Next come reduced-fat dairy foods, lean meats and fish, nuts, and
- Higher up -- and meant to be eaten less frequently -- come whole grains,
unrefined grains and pastas.
- At the top -- to be eaten sparingly if at all -- come refined grains,
potatoes, and sweets.
Obese participants in the study were instructed to eat nonstarchy
vegetables, fruits, beans, nuts, and dairy products. They were told to eat
carbs with protein and healthful fat at every meal and snack. And they were
told to eat until they were full and to snack when hungry.
Other obese study subjects were put on a traditional, low-fat/low-calorie
diet. Both groups were asked to exercise regularly and were given lifestyle
"Those in the low-glycemic-diet group were told to eat as much as they
wanted and to snack when hungry," Ludwig says. "Yet after a year, they
lost fully as much weight as those told to cut back on fat and to cut back on
calories. But they did better in terms of heart disease risk
Weight, Heart Risk Down
After 12 months on the diets, the slow-carb group lost 7.8% of their body
weight compared with 6.1% in the low-fat-diet group.
Levels of triglycerides -- blood fats linked to heart disease -- decreased
much more in the slow-carb group. The levels were down 37% in the slow-carb
group compared with 19% in the low-fat group.
Levels of a factor that increases blood clots - called plasminogen activator
inhibitor - decreased by 39% in the slow-carb group but increased 33% among the
low-fat dieters. Blood clots in the heart arteries are usually the cause of