Last updated on April 9th, 2017
What is the healthiest diet? A study at the Norwegian University of Science and Technology (Feed your genes – NTNU) examined molecular evidence to try to answer the question.
The result, according to the Norwegian biologists, is that the best diet for your genes is one-third protein, one-third fat and one-third carbohydrates.
It’s not exactly a low-carb diet, but it is reduced carb. Indeed, such an evenly balanced diet would represent a 50% or greater reduction in carb intake for the average American — and the average Norwegian. According to Professor Berit Johansen, “a diet with 65 per cent carbohydrates, which often is what the average Norwegian eats in some meals, causes a number of classes of genes to work overtime.”
In the study, researchers gave “slightly overweight” adult volunteers different diets to eat, and examined the diets’ effects on gene expression. The genes found to “work overtime” on a higher-carb diet were those associated with inflammation in the body, and also those implicated in several “life-style” diseases — including dementia, heart disease, diabetes, and some cancers.
Johansen recommends cutting down on “potatoes, rice and pasta” and eating “real mayonnaise and sour cream, and . . . real cream in your sauce.” There are elements of Conventional Diet Wisdom in her advice, though. She warns people to control portion-size, and to keep in mind that “fat is twice as calorie-rich as carbohydrates and proteins.” More conventional still is her assertion that “we shouldn’t eat too much saturated animal fat, but monounsaturated vegetable fats and polyunsaturated marine fats are good.”
However, the study provides more support for reducing carbs in the typical Western diet than for any other change. While Johansen states that neither a low-carb nor a high-carb diet is best, she goes on to say that “a low-carb diet is closer to the right diet. A healthy diet shouldn’t be made up of more than one-third carbohydrates (up to 40 per cent of calories) in each meal, otherwise we stimulate our genes to initiate the activity that creates inflammation in the body.”
For a person eating 2,000 calories a day, the diet recommended by the Norwegian researchers (one-third each of protein, fat and carbs) would result the consumption of about 167 grams of carbs a day. (I assume it was total carbs being studied, not net.)
A couple factors worth noting are that the subjects ate powdered diets so that as many dietary variables as possible could be controlled and that a very low-carb, high-fat diet does not seem to have been tested.
The bottom-line finding, though, strongly supports significant carb reduction: “a carbohydrate-rich diet, regardless of whether or not a person overeats, has [negative] consequences for genes that affect the lifestyle diseases.”