All Low-Fat Diets Are Not Equal, Stanford Study Shows
A low-fat diet rich in vegetables, fruits, whole grains and beans has twice the cholesterol-lowering power of a conventional low-fat diet, according to a new study from the Stanford University School of Medicine.
In other words, a meal of spinach salad, egg and oatmeal-carrot cookies is healthier for your heart than stir-fried lean beef and asparagus and low-fat chocolate chip cookies, even when both meals contain the same amount of saturated fat and cholesterol.
The finding, published in the May 3 issue of the Annals of Internal Medicine, comes from a meticulous comparison of two low-fat diets. One, the conventional diet, focused solely on avoiding harmful saturated fat and cholesterol. Diners ate such foods as frozen waffles and turkey bologna sandwiches. The second diet included the same proportions of fat and cholesterol, plus lots of plant-based foods in accordance with American Heart Association guidelines. Those diners ate such foods as hot grain cereals and vegetable soups.
Both diets lowered total and low-density lipoprotein (LDL, or "bad") cholesterol over the course of the four-week study. The conventional diet produced, on average, a 4.6 percent LDL decrease. But the plant-based diet beat that hands-down: It achieved, on average, a 9.4 percent decrease in LDL. Researchers found no significant differences in changes in triglycerides or high-density lipoprotein ("good") cholesterol.
"The effect of diet on lowering cholesterol has been really minimized and undermined by a lot of clinicians and researchers saying, 'Yes, it has an effect but it's really trivial: It would be better to put you on drugs to control your cholesterol," said Christopher Gardner, PhD, assistant professor (research) of medicine at the Stanford Prevention Research Center and lead author on the National Institutes of Health-funded study. "But we think part of the reason was that we weren't really giving diet a fair shake. We were so focused on the negative, just what to avoid, and not what to include."
The bottom line? Mother knows best: Do eat your veggies