Harvard Nutrition Expert Explains Why 'Everything In Moderation' Is Useless Diet Advice

The "everything is fine in moderation" approach to dieting may seem like a fair and balanced approach to nutrition, but according to Harvard Medical School nutrition and obesity expert Dr. David Ludwig, it's essentially useless in practice.

"There [are] some things you [should] eat a lot of, and I would put things like olive oil, avocado, nuts in that category," Ludwig said in an interview with Tech Insider. "There are other things you [should] really minimize, especially if you're dealing with pre-diabetes or some other metabolic problem. You don't want to go moderate with sugar — whatever that means. You want to get rid of as much of it as you can."

Pointing to a study in the New England Journal of Medicine in which more than 7,000 people at risk for heart disease were given one of three diets — a Mediterranean diet with plenty of olive oil, a Mediterranean diet with lots of nuts, or a low-fat diet — Ludwig noted that that the researchers had to stop the study early because heart disease rates in the two groups eating the healthy fat Mediterranean diets dropped so much that it became "unethical to keep the control group eating the low-fat diet," Ludwig said.

Ludwig's recommendations are in line with the USDA's updated nutrition guidelines for the American public, which recommends adopting a Mediterranean diet as one of three diets linked to longevity, and cutting down on added sugars to 10 percent of one's daily calories.