Could This Diet Reverse Your Biological Age?
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Could This Diet Reverse Your Biological Age?

New research suggests the fasting-mimicking diet could promote longevity

Fasting diets are firmly in the spotlight right now. Last month everyone was talking about intermittent fasting after Rishi Sunak said he kicks off every week with a 36-hour fast, and now the fasting-mimicking diet is dominating conversation. As the name suggests, this is a cyclical nutritional programme which aims to mimic the effects of fasting, requiring you to eat specific foods and drinks for a five-day period. 

While the diet has been around for a while, interest around it has resurfaced following a new study led by the University of South California Leonard Davis School of Gerontology. The research suggests that cycles of the fasting-mimicking diet can reduce biological age in humans – essentially, keeping us younger for longer. So what does this eating plan involve? And could it really be the key to longevity? We asked nutritionist Kim Pearson.

The Fasting-Mimicking Diet: A Nutritionist’s Take

What Is The Fasting-Mimicking Diet?

The fasting-mimicking diet, or FMD, is a concept developed by Professor Valter Longo and researchers at the University of Southern California, who have carried out extensive research into periodic fasting. Fasting mimicking diets (FMDs) provide the benefits of water only fasting but with a specially designed, plant-based diet plan that does not trigger nutrient sensing pathways. The FMD consists of plant-based soups, whole food energy bars, snacks and drinks, and tea portioned out for five days. It also includes supplements that provide high levels of minerals, vitamins, and essential fatty acids. The provision of specifically designed plant-based meals and supplements means that the body still receives essential nutrients whilst remaining in a fasted state.

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What Are The Potential Benefits?

FMDs are the result of two decades of research and millions of dollars of federal funding. In studies, FMDs reduced risk factors for ageing and diseases including diabetes, cardiovascular disease and cancer. Benefits include reduced visceral fat and levels of systemic inflammation. Prolonged fasting has been shown to induce autophagy – a process that helps to maintain healthy cellular function. During autophagy, cells repair, regenerate and rid themselves of debris. 

A recent USC study found that cycles of a fasting-mimicking diet reduced signs of immune system ageing as well as insulin resistance and liver fat in humans, resulting in a lower biological age. ‘This study shows for the first time evidence for biological age reduction from two different clinical trials, accompanied by evidence of rejuvenation of metabolic and immune function,’ said Professor Longo, senior author of the study.

Who Would You Recommend This Diet For?

I recommend fasting-mimicking diets to clients looking to improve their metabolic health, promote longevity and kickstart weight loss. Fasting-mimicking diets provide the health and cellular regeneration benefits of water-only fasting but without having to give up food altogether. For many individuals, a programme which allows food can seem less daunting compared with consuming water alone for several days. Compared with periodic water only fasting there is reduced risk of certain contraindications.

Who Might The Fasting-Mimicking Diet Not Be Suitable For?

There are potential contraindications with medical conditions such as diabetes and heart conditions. If you have a health condition or are taking medications you should always check with your doctor before undertaking a FMD. Fasting for long periods of time carries the risk of low blood sugar and fainting. It’s not uncommon for individuals to experience side effects such as headaches. FMDs cannot be done by individuals who are allergic to the ingredients in the programme which include nuts and soya. I would not recommend FMDs to anyone with eating disorders. 

Kim Pearson qualified as a nutritionist at London’s Institute for Optimum Nutrition in 2008 and has worked in the field of nutrition and health for 20 years. She specialises in weight loss, metabolic health, and longevity. In addition to heading up her UK team of nutritionists, Kim is the clinical director of RoseBar longevity club in Ibiza. She is a full member of CNHC (Complimentary and Natural Healthcare Council), BANT (British Association of Applied Nutrition and Nutritional Therapy) and the Guild of Health Writers. Follow Kim on Instagram @kimmypearson and find out more about her work at