The Mediterranean diet, a model of longevity, is updated and becomes ‘3-dimensional’, adding for the first time to the quantity and quality of nutrients also their temporal location in harmony with biological, hormonal and metabolic rhythms over 24 hours. This new approach – developed by the Italian Society of Endocrinology (Sie) together with the Italian Association of Dietetics and Clinical Nutrition (Adi) and published in ‘Current Nutrition Reports’ on the eve of World Obesity Day on 4 March – redesigns the pyramid of the traditional Mediterranean diet by synchronising the dietary recommendations, which remain unchanged, with the biological clock and hormonal oscillations (insulin, cortisol and melatonin), thus offering a concrete strategy against obesity and metabolic diseases.
The same foods at different times produce different effects
“The Mediterranean diet is no longer just a question of what one eats, but above all when one eats it,” explains Diego Ferone, Sie president and professor of Endocrinology at the University of Genoa. ‘The most recent scientific evidence,’ Ferone further emphasises, ‘shows that metabolism is profoundly regulated by hormones and follows a circadian organisation. Key hormones such as insulin, cortisol, melatonin, leptin and ghrelin fluctuate throughout the 24 hours, modulating the metabolic response to nutrients, appetite, energy expenditure and sleep quality. Eating the same foods at different times of the day can therefore produce different metabolic effects, with major implications for the risk of overweight and obesity and endocrine dysfunction associated with weight gain, not only type 2 diabetes mellitus, but also alterations in endocrine gland function’. The new model therefore introduces the time dimension, inserting sun and moon symbols next to the pyramid design to indicate the best times to consume certain foods.
Evening increases the risk of glycaemic spikes and fat accumulation
“The sun symbol suggests daily consumption within the first part of the morning, to take advantage of maximum insulin sensitivity, of complex carbohydrates (cereals, pasta and bread, preferably wholemeal), pulses, fruit, vegetables and vegetables. The moon symbol, on the other hand, orients instead towards evening meals, when the risk of glycaemic peaks and fat accumulation increases, the consumption of lean proteins, vegetables and sleep-friendly foods such as nuts, seeds and dairy products, rich in tryptophan and melatonin that favour rest and night-time muscle regeneration,’ illustrates Luigi Barrea, first signatory of the update document and Sie advisor, professor of Clinical Nutrition and Applied Dietetics at the Pegaso University of Naples. For Barrea, ‘consuming 40 grams of protein before bed can increase muscle protein synthesis by 33%, counteracting muscle mass loss. And shifting 5 per cent of energy from fats to carbohydrates during breakfast helps drastically reduce the risk of metabolic syndrome’. As for extra virgin olive oil, ‘it remains the undisputed protagonist, which can be used flexibly for its universal anti-inflammatory and antioxidant properties, both during the day and in the evening,’ specifies Massimiliano Caprio, Professor of Endocrinology at the San Raffaele Telematic University in Rome. ‘High consumption of evo oil,’ he recalls, ‘reduces the risk of cardiovascular disease by 39% and halves mortality. And for every increase of just 10 g per day of evo oil, the cardiovascular risk is further reduced by 10%’.
Individual chronotypes: from owls to larks
The real innovation of the model, the experts point out, is the focus on the individual chronotype. The ‘owls’, people with a serotonous chronotype, tend to skip breakfast and concentrate food intake in the evening hours, when insulin sensitivity is reduced and glycaemic regulation is less efficient, with potential negative consequences on metabolic health. The new pyramid of the Mediterranean diet helps them realign gradually, concentrating caloric load in daylight hours to avoid metabolic jetlag, i.e. misalignment with internal biological rhythms due to irregular social activities. Larks’, early risers, on the other hand, are naturally predisposed to a greater adherence to the Mediterranean diet, and benefit from a rich breakfast, a hearty lunch and a light, mainly protein-based dinner. The new pyramid is not just a food guide, but a manifesto reinforcing the concept of the Mediterranean diet as a global lifestyle. “In fact, the new model also includes physical activity in the sunlight, quality sleep, conviviality, and respect for seasonal biodiversity that contribute in an integrated manner to maintaining endocrine-metabolic health,’ points out Salvatore Cannavò, president-elect of the Sie and professor of Endocrinology at the University of Messina. ‘In line with Unesco’s recognition of the Mediterranean diet as an intangible cultural heritage of humanity, the new model enhances a holistic vision that combines tradition, sustainability, and scientific innovation. ‘Integrating the temporal and hormonal dimensions into the Mediterranean diet means updating an extraordinary cultural heritage in the light of the most modern endocrinological knowledge. This new pyramid represents a useful tool not only for prevention, but also for clinical practice, with a view to increasingly personalised and physiologically based nutrition,’ Ferone concludes.
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