The Prospective Urban Rural Epidemiology study is a large cohort study of people ages 35 to 70 in 17 countries with a median follow-up of 7.4 years.

Scientists studied the dietary intake of 135,335 individuals using a validated food frequency questionnaire. The subjects were stratified into quintiles of nutrient intake (carbohydrates, protein, and fat). The results were published on the website of the journal The Lancet.

The researchers found a higher carbohydrate intake was associated with a 28 percent increase in risk of total mortality in the highest vs. the lowest quintile. Intake of total fat was associated with a 23 percent lower risk of total morality.

It did not matter whether the fat was saturated, monounsaturated, or polyunsaturated — they all showed lower risk. Higher saturated fat was associated with a 21 percent lower risk of stroke.

Dietary fat has been vilified in our society. About 50 years ago, our government told us to eat more carbohydrates in the form of grains. We complied, and we became the most obese people on the planet.

Now, nearly two-thirds of Americans are overweight or obese.

The human body needs dietary fat for building cell membranes. I council patients to limit refined foods, particularly grains, sugar, and flour.

More information about a healthy diet can be found in my book, The Guide to Healthy Eating.