High-carb diet for longevity

Paleo practitioners, Atkins advocates and the anti-gluten brigade have got it all wrong, according to the latest research from the University of Sydney’s Charles Perkins Centre. The ideal diet to fight obesity while boosting levels of the ‘fountain of youth’ hormone is low in protein and high in carbohydrates.

Fibroblast Growth Factor 21 (FGF21) is a hormone produced by the liver that has an important but little understood role in diabetes, obesity and longevity. According to the academic director of the Charles Perkins Centre, Professor Stephen Simpson, “FGF21 has been shown to be elevated in really paradoxical conditions: in starvation and obesity, in cases of both insulin resistance and sensitivity and when there’s a high and a low intake of food.”

FGF21 is already in use as a therapeutic target for diabetes although researchers admit they are uncertain exactly how it works in curbing appetite, moderating metabolism, improving the immune system and boosting longevity.

To get a clearer picture of these mechanisms the Charles Perkins Centre team came up with 25 diets ranging from 5–60% protein and 5–75% carbohydrate and fat. They tested these diets on 858 mice and assessed the ways in which certain macronutrients interacted with each other to influence FGF21 levels. Interestingly, they found that the mice on the high-carb diets compensated for the increased FGF21 levels by burning more energy, while for those in a starvation state, the FGF21 actually promotes energy conservation.

Lead author Dr Samantha Solon-Biet said, “Despite the popularity of high protein ‘paleo’ diets, our research suggests the exact opposite may be best for us as we age — that a low-protein, high-carbohydrate diet was the most beneficial for late-life health and longevity.”

Co-author Professor Stephen Simpson said: “It appears that FGF21 is really switched on by a low protein intake, and its metabolic effects vary on whether it’s coupled with high energy or low energy.”

The team hope that this research will lead to greater understanding of how FGF21 is activated and can be used to treat chronic health problems like diabetes and other metabolic disorders. The first step will be updated nutritional guidelines so patients can tailor their diets in order to maximise the benefits of FGF21.

Dr Samantha Solon-Biet believes, “These findings take us one step closer to understanding how FGF21 works, and as an extension of that to be able to use FGF21 to help people live longer and healthier lives.”

This research is published in Cell Metabolism and was conducted in collaboration with EWOS Innovation (Norway), Pennington Biomedical Research Center (USA), Macquarie University and the ANZAC Research Institute.