Study gives nod to low-carb diets
Casting fresh doubt on a widely held dietary belief, a new study of low-carbohydrate diets found that eating higher amounts of fat doesn’t increase cardiac risk for women.
The report in today’s New England Journal of Medicine also found that consuming higher amounts of vegetable fat greatly reduced the chance of heart disease.
The findings mean “you don’t have to restrict everything to lose weight or reduce your risk for heart disease,” said Kathleen Rigol, a spokeswoman for the American Heart Assn. who was not connected with the study.
But Gary D. Foster, an obesity researcher at Temple University in Philadelphia, cautioned against interpreting the study as an excuse to load up on bacon and fatty meats, which are key attractions of the popular low-carbohydrate Atkins diet.
“It would be a mistake to go out and overeat any one nutrient,” he said. “Quantity still counts.”
Scientists from Harvard University and UCLA looked at dietary information collected over 20 years from 82,802 women who participated in the Nurses’ Health Study, a federally funded research project begun in 1976.
Researchers divided them into 10 categories depending on the proportions of carbohydrate, protein and fat in their diets.
Consumption of carbohydrates, such as pasta and bread, in women’s diets ranged from relatively high 58.8% of calories to moderately low 36.8%.
All participants consumed more than 7% of calories from saturated fat, above the level recommended by the American Heart Assn.
Researchers counted 1,994 cases of coronary heart disease during the study. After adjusting for various risk factors, such as smoking, scientists found no differences in cardiac risk among the groups.
In a separate analysis, researchers divided the women based on their consumption of vegetable fat, such as olive oil. Women who derived the highest percentage of calories from vegetable fat had 30% lower risk of heart disease than those who ate a higher proportion of animal fats.
“I think the take-home message is that not all low-carb diets are the same,” said lead author Thomas L. Halton, an instructor at Simmons College in Boston who did the research while a doctoral student at the Harvard School of Public Health.
“There is no risk in doing a low-carb diet, but you can reduce your risk by picking healthier sources of fat,” he said.
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