By Marika Sboros

It’s not the definitive word for best weight loss diets but it’s close. And it doesn’t venture into the contentious plant- versus animal-food divide. A major new Harvard study shows that replacing carbohydrates with fats speeds up metabolism.

It overcomes one of the biggest hurdles in conventional weight-loss diets: the “plateau”. That is the metabolism slowdown that prevents weight loss on conventional diets.

It’s why so many lose some weight but stay hungry and find it increasingly harder to lose more.

The Harvard study in the BMJ is well-designed and randomised. It is also one of the largest feeding studies ever conducted, say the authors. Add recent US research by Virta Health on low-carb, high-fat (LCHF) diets to reverse type 2 diabetes and experts say it’s a recipe for speedy, safe, sustainable weight loss.