The study, published in The Lancet found that high fat diets were associated with a lower risk of mortality - and those diets with a high intake of carbohydrates were associated with a higher risk.
The study involved more than 135 thousand people from 18 countries, and found that high fat diets were associated with a lower risk of mortality. But those diets with a high intake of carbohydrates were associated with a higher risk.
It suggests that rather than focusing on reducing fat intake in diets, healthy food guidelines should instead focus on reducing carbohydrate intake.
Professor Grant Schofield the director of the Human Potential Centre at AUT says this shows it is finally time to move on from banishing dietary fat, including saturated fat - and that it is better to concentrate on getting people to eat less highly processed and refined foods, especially sugar and highly refined carbohydrates.
"If our food was clearly recently alive in nature, that's a good start to a healthy diet."