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Anti-Paleo Diet Boosts Life-Extending Hormone

New research from the University of Sydney’s Charles Perkins Centre suggests that a low protein, high carbohydrate diet may be the most effective for stimulating a hormone with life-extending and obesity-fighting benefits.

The findings, published in Cell Metabolism, paint a clearer picture of the role of the little-known “fountain of youth” hormone fibroblast growth factor-21 (FGF21), which is produced primarily in the liver.

Previous studies have shown that FGF21 plays a role in curbing appetite, moderating metabolism, improving the immune system and extending lifespan. It is also currently used as a therapeutic target for diabetes, yet little is known about how this hormone is triggered and released in the body.

“Despite the popularity of high protein ‘paleo’ diets, our research suggests that 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,” said lead author Dr Samantha Solon-Biet.

“The nutritional context in which FGF21 is most elevated is dependent on the balance of protein to carbohydrate, and this balance was also shown to be important in how this hormone helps to mediate protein hunger.

The researchers fed 858 mice one of 25 diets that varied in protein, carbohydrate, fat and energy content. They then mapped these macronutrient variables to investigate how nutritional balance affected FGF21 levels.

The study revealed that when high carbohydrate diets increased FGF21 levels, the mice compensated for the excess by burning more energy. Conversely, FGF21 promoted energy conservation during starvation conditions.

“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,” said co-author Prof Stephen Simpson. “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.

“Discovering more about how FGF21 is activated opens the way for nutritional interventions to chronic health problems, including as a potential drug target for the treatment of diabetes and other metabolic disorders. The next step will be to identify FGF21’s exact signalling pathway in order to better tailor our diets and nutritional guidelines to generate the maximum benefit from this essential hormone.”