Diet of Maximum 30% Fat Extends Life Only Months, Researchers Say

Trimming dietary fat to no more than 30% of calories consumed would add only months to the lives of average Americans, researchers say in a report published today in the Journal of the American Medical Assn.

Thirty-seven percent of the average American’s calorie intake is fat, whereas a maximum of 30% is recommended by dietary experts. Consuming excess fat raises the likelihood of developing coronary heart disease and cancers of the breast, colon and prostate.

Yet reducing fat to 30% of calories would put off death for only about 2% of the 2.3 million Americans who die each year, said analysts led by Dr. Warren S. Browner of the UC San Francisco School of Medicine.

“This 2% benefit, equivalent to an increase in average life expectancy of three to four months, would accrue chiefly to people over the age of 65 years,” the authors wrote. “These results may be disappointing to those who believe that following a healthier diet will protect them from early death.”

Dr. Margo Denke, assistant professor of internal medicine at the Center for Human Nutrition at the University of Texas Southwestern Medical Center, said the report is “interesting from a population standpoint, but it should not be used to make individual decisions.”

Low-fat diets do not necessarily help everyone, but they act like insurance policies to pay big benefits--including staving off death or debilitating symptoms--in individuals prone to heart disease, she said.

Denke also criticized the study for failing to take into account that for every American who dies of heart disease, four others have heart disease symptoms that could be caused by too much fat in their diets.