TUESDAY, May 3, 2005 (HealthDay News) -- Here's the lowdown on low-fat diets -- they're not all equal.
A Stanford University School of Medicine study found that a low-fat diet that features plenty of fruits, vegetables, whole grains and beans is twice as effective as a conventional low-fat diet at reducing "bad" low-density lipoprotein (LDL) cholesterol.
The study included 120 adults, aged 30 to 65. One group (61 people) was put on a conventional low-fat diet that focused solely on avoiding harmful fat and cholesterol. They ate foods such as turkey bologna sandwiches and frozen waffles.
The other group (59 people) ate a diet that included the same proportions of fat and cholesterol, along with plenty of plant-based foods in accordance with American Heart Association (AHA) dietary guidelines.
Over the course of the four-week study, both diets reduced levels of total and LDL cholesterol. However, the plant-based diet achieved an average 9.4 percent reduction in LDL, compared with a 4.6 percent LDL decrease achieved by the conventional low-fat diet.
There were no significant differences in changes in triglycerides or "good" high-density lipoprotein (HDL) cholesterol.
The study appears in the May 3 issue of the Annals of Internal Medicine.
The results show that people need to do more than simply avoid fat and cholesterol -- they need to eat vegetables and other nutrient-dense foods, the study authors said.
"We would really hope that people would appreciate the new American Heart Association guidelines. Include more whole grains and vegetables and beans and colors -- not iceberg lettuce, but red bell peppers and carrots and broccoli and red cabbage and the really colorful foods. Those are all really low in saturated fat and cholesterol, and they're really high in other nutrients and phytochemicals that are good for you," study author Christopher Gardner, an assistant professor of medicine at the Stanford Prevention Research Center, said in a prepared statement.
He noted that a plant-based diet isn't necessarily a vegetarian diet, but does include a foundation of whole grains, beans, nuts, seeds and fruits. The AHA guidelines recommend at least five daily servings of fruit and vegetables and at least six daily servings of grains, with an emphasis on whole grains.
Here's where you can find the American Heart Association's dietary guidelines.