Living longer with the right diet - is that possible?

And is there a point in life when it's too late for healthier habits?

06-May-2022 - USA

(dpa) The search for sources of eternal youth and long life has accompanied mankind for centuries. At least for longevity, scientists believe they have found a very strong factor: the right diet. Unlike genes or certain living conditions, it can be influenced. Increasingly, it's not just a question of what goes on the plate, in what quantity and quality - but also when.

In a review paper published in the scientific journal "Cell," U.S. gerontologists Valter Longo and Rozalyn Anderson summarize the state of knowledge. Friends of calorie bombs such as menus of burger, chips and soda or soul comforts such as white chocolate must now be very strong: The duo talks about better limiting energy intake and fasting more often to minimize disease risks and increase life expectancy.

The core characteristics of a probably optimal nourishing form outline it - first of all quite technically - in such a way: middle to high admission of coal hydrates (45 to 60 per cent) from high-quality sources; little, but sufficiently protein from usually vegetable sources; 25 to 35 per cent mainly vegetable-based fat.

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Translated for everyday cooking, that means "lots of legumes, whole grains and vegetables; some fish; no red or processed meat and very little white meat; little sugar and refined grains; good amounts of nuts and olive oil and some dark chocolate," Longo says, according to a news release. The optimal approach, he says, is to eat only within a daily window of eleven to twelve hours and to have several periods of fasting throughout the year.

Longevity is Longo's life's work, so to speak: he is director of the Longevity Institute at the University of Southern California in the USA and author of several books. On his website, he gives tips on how to stay young and lists so-called longevity recipes. These are likely to disappoint meat lovers, but they don't sound completely hostile to pleasure either: couscous with fish, bread salad from Tuscany and pasta with eggplant. Longo also founded a company with products for fasting concepts, which he states in the appendix of the study.

Longo and Anderson emphasize in their work that an anti-aging diet should be adapted to the individual. There is no one solution that is just as appropriate for a fit 20-year-old as for a 60-year-old with metabolic disease. Gender, age, lifestyle, health status and genes must be taken into account, they write. For example, people over 65 may need extra protein, they say.

For Kristina Norman, a researcher on aging at the German Institute of Human Nutrition, such adjustments are a very important point: "In old age, it is often difficult to take in enough protein. Too little of it can lead to muscle loss and subsequently to an increased risk of falls and fractures. So then eating a little more meat than generally recommended can be advisable."

The author duo looks at a wide range of work: Starting with studies on yeast, worms or flies to clinical data and modeling. In addition, there are findings on traditional diets in places where many people live to a very old age.

"A study in which a group is assigned the diet recommended by Longo, and the lifespan at the end is compared to a control group, would be very difficult to implement. That's why the authors approach it by pooling different evidence," Norman said. She considers Longo's and Anderson's theses to have convincing evidence.

There are many parallels, she said, to well-known recommendations, such as those of the German Nutrition Society, and also to a menu that scientists proposed some time ago for a diet that is both healthy and environmentally sound. "Contrary to what is often assumed, recommendations on healthy eating do not change every few years. Overarchingly, they are very stable," Norman said. "The Longo study can be seen as old hat, but the topic has been rethought and is increasingly supported by evidence."

For Bernhard Watzl, former head of the Institute of Physiology and Biochemistry of Nutrition at the Max Rubner Institute, the review primarily shows that quantity and quality of diet are critical to long life, he said. "The rule is to take in too little energy rather than too much." As for the underlying mechanisms in the body, he explains, "The more a system is challenged, the more it wears out." Rather, he says, it is important to challenge the body at a low level.

On the subject of fasting, however, Watzl is less convinced by the data to date than Longo: "Fasting is only something for people who don't manage to limit their energy intake," he said. In that case, for example, the temporary abstention from food could help to re-sensitize certain receptors in the body.

In general, it's never too late for healthy eating over the course of a lifetime, Watzl emphasized. However, for some diseases that develop in the body over decades, the earlier the better, he says. Longo replied to a dpa query that, according to a study, even 60- or 80-year-olds could still increase their life expectancy by several years if many of the suggestions he also propagated were implemented. The study said the greatest benefits would come from eating more legumes, whole grains and nuts, and less red and processed meat.

When it comes to food quality, Watzl sees some habits in this country as positive: eating whole-grain bread or muesli, for example. "However, too much cheese or sausage is quickly added to the bread. Or light-colored bread is eaten." Watzl is also critical of highly processed foods - because of the additives, but also because of the rapid availability of nutrients. That overtaxes the metabolism.

In general, Longo and Anderson advise small changes in diet and discourage radical change. Many are likely familiar with the problem of dieting: If the plan is too restrictive, it cannot be sustained over the long term. The result is a yo-yo effect.

Note: This article has been translated using a computer system without human intervention. LUMITOS offers these automatic translations to present a wider range of current news. Since this article has been translated with automatic translation, it is possible that it contains errors in vocabulary, syntax or grammar. The original article in German can be found here.