Who wants to lose weight, feel great, and live a long and healthy life, and what does it take to achieve these goals? Diet and exercise are equally important in long-term health, but let’s look at what recent science is telling us about the healthiest diets.
This article will rely heavily on University of Southern California professor Valter Longo’s work because I consider it to be the gold standard for nutrition research, and his recommendations in his book The Longevity Diet are well-supported with both data and good logic. Longo is the director of the Longevity Institute at USC and the IFOM Program on Longevity and Cancer in Milan.
He comes from an area of Italy known for very long lives, and part of his research focus has been looking at similar areas around the world and why those people live so much longer than normal.
Longo’s Longevity Diet
The short summary of Longo’s “Longevity Diet” is as follows:
- Eat mostly plant-based foods, with occasional low-mercury fish or other seafood (2-3 times a week) and lots of nuts and olive oil
- Generally eat modest amounts of protein, whether it’s plant-based or animal-based
- Very limited or no dairy; goat’s milk and cheese are okay
- Minimize saturated fats and sugar
- Eat foods from your ancestral homelands as long as they are otherwise healthy
- Eat 2-3 meals a day, ideally two solid meals and one snack, in a 10-12 hour window, and don’t eat 3-4 hours before bedtime
- Take multivitamins every three days
- A few times a year, if you are under age 65-70 and otherwise healthy, do a five-day water fast or a “fasting-mimicking diet,” which includes food but mimics the benefits of actual fasting.
Longo’s longevity diet is a plant-centric diet, which means that the large majority of what you eat is plants, fruits, nuts and legumes. It’s not going to kill you to eat occasional meat or dairy, but if you are under age 65, Longo recommends that you keep these very low or absent in your diet. However, if you are over age 65, Longo recommends eating higher portions of animal protein along with good sources of plant protein because our bodies are programmed to lose muscle mass as we age.
Longo argues against a strictly vegan diet or cutting out oil, as some researchers have recommended. He argues that consumption of fish, nuts and olive oil is associated with reduced risk of heart disease as well as very long lives in communities in Japan, Greece, and Italy (the famous “blue zones” where people are living to 100 years old far more than the average population).
There are definitely good ethical and environmental reasons to be a strict vegan, and a later piece will examine these arguments, but Longo argues that being strictly vegan, as opposed to mostly vegan, is not optimal for human health.
Longo advises strongly against the various “keto” diets that include high animal protein, high fat, and low carbs. While these diets will help you lose weight in the short term through increased ketogenesis, they are likely to lead to potentially serious health problems down the road.
Longo writes: “If we examine the laboratory studies, we see that both high protein intake and high saturated fat intake are associated with aging and disease, an additional and key vote against a high-protein, high-saturated-fat diet.” If there is any doubt, he adds later in the book that this kind of diet is “the worst of all possible regimens” for overall mortality risk, cancer risk, heart disease and diabetes.
In short, diet and good exercise may be the magic pill for health and longevity that isn’t available (yet) in actual pill form. Longo doesn’t promise immortality, of course, in following his recommendations. But he does suggest that we’ll maximize our chances of living to a hundred or more.
The new science of fasting
Author Michael Pollan got basic eating advice pretty much right in his well-known book The Omnivore’s Dilemma: “Eat food, not too much, mostly plants.” .
Unpacking Pollan’s statement a little, his point of view is that we should eat real, whole foods, not overly processed pretend foods; we should eat in moderation; and we should stick mostly to plants, fruits, and nuts, with occasional meat and fish to taste.
This is still great advice, but we are now at the point that, due to the efforts of researchers such as Longo, we can make more specific recommendations based on well-established science.
Longo would probably agree entirely with Pollan’s three-part mantra, though he doesn’t discuss it explicitly in his book. Where Longo goes beyond the mantra is in his recommendations on intermittent fasting and the fasting-mimicking diet.
Longo recommends eating within a 10-12 hour window each day, which is a type of intermittent fasting. He also recommends engaging in either a water (no food) fast or a fasting-mimicking diet, which achieves the same or similar results as actual fasting, two or more times a year.
The benefits of caloric restriction and intermittent fasting are now well-established. We don’t really understand yet why evolution built us this way, but it seems that when we stress our body by mimicking mild starvation, it responds by cleaning things up inside our cells as well as killing off sickly cells, and, more generally – as Josh Mitteldorf argues here – by slowing down many of the programmed aging aspects that are built into our genes. This includes increased telomere length, which I’ll cover in a later article.
Many times in his book, Longo stresses the need to consult with a doctor or other medical professional before engaging in any fast longer than a day.
Can diet really prevent or even cure disease?
This leads to what is perhaps the most groundbreaking area of Longo’s research: the fact that he and other researchers have now developed a body of work that shows remarkable preventive and even curative effects of diet, fasting, and exercise on many serious diseases. As he explains, “Genetic or dietary interventions can not only delay diseases but actually eliminate a major portion of chronic diseases in mice, monkeys, and even humans to extend longevity.” Mice fed various versions of Longo’s longevity diet have lived up to 40 percent longer than average.
Longo presents good data showing that the diet he recommends does not only lead to optimal weight and health but also provides strong protection against the major ailments of old age, including cancer, cardiovascular disease, diabetes, and even Alzheimer’s and other neurodegenerative diseases.
For example, Longo shows (citing a 2007 study ) that cardiovascular disease and cancer occur with remarkably lower frequency among Okinawans, and the Japanese more generally, than among Americans. Longo and the study’s authors pin the difference on diet.
I’m embarking on my own adventure using Longo’s longevity diet to improve my health and longevity. I’ll report back with results at a later date.
A key benefit of Longo’s diet recommendations is that they can be eased in and nothing needs to be eliminated entirely from your diet. For people who prefer not to go “cold turkey” on giving up things they like to eat, this can be a real benefit. At the end of his book, Longo includes a two-week meal plan for getting started on his longevity diet.
Eating a plant-centric diet can be very fulfilling and lead to all sorts of tasty new meals. Once you get past the notion that a “good meal” needs to have some kind of meat, a whole new world of tastes and satisfaction awaits.
 Pollan, M., & Andrews, M. (2015). The omnivore’s dilemma: The secrets behind what you eat. Listening Library.
 Willcox, B. J., Willcox, D. C., Todoriki, H., Fujiyoshi, A., Yano, K., He, Q., … & Suzuki, M. (2007). Caloric restriction, the traditional Okinawan diet, and healthy aging. Annals of the New York Academy of Sciences, 1114(1), 434-455.