What follows is the optimal diet for minimizing disease and maximizing a healthy lifespan based on the Five Pillars.
Follow a pescetarian diet. Aim for a diet that is close to 100 percent plant- and fish-based, limiting fish consumption to two or three portions a week and avoiding fish with high mercury content (tuna, swordfish, mackerel, halibut). If you are past age sixty-five and start to lose muscle mass, strength, and weight, introduce more fish into the diet, along with other animal-based foods commonly consumed by populations with record longevity, like eggs and certain cheeses (preferably feta or pecorino) and yogurt made from goat’s milk, all of which are commonly consumed in high-longevity areas.
Consume low but sufficient proteins. Consume 0.31 to 0.36 grams of protein per pound of body weight per day. If you weigh 130 pounds, that comes to about 40 to 47 grams of protein per day, of which 30 grams should be consumed in a single meal to maximize muscle synthesis. If you weigh 200 to 220 pounds and have 35 percent body fat or higher, 60 to 70 grams of protein per day is sufficient, since fat cells require lower levels of protein than muscles. Since this minimum requirement can change from person to person, it is preferable to occasionally consult a dietitian, to make sure that a healthy, lean body mass is maintained. Protein intake should be increased slightly after age sixty-five in individuals who are losing weight and muscle. For most people, a 10 to 20 percent increase (5 to 10 grams more per day) is sufficient. Finally, the diet should be free of animal proteins (red meat, white meat, cheese) with the exception of proteins from fish, but relatively high in vegetable proteins (legumes, nuts, etc.) to minimize the former’s negative effects on diseases and maximize the latter’s nourishing effects.
Minimize bad fats and sugars, and maximize good fats and complex carbs. Part of the confusion and constantly changing recommendations around diet stem from the oversimplification of food components and their categorization into fats, carbs, or proteins. Every day we hear about “low carb versus high carb” or “low fat versus high fat.” It shouldn’t be a question of either/ or, but of which type and how much of each. In fact, your diet should be rich in good unsaturated fats, such as those found in olive oil, salmon, almonds, and walnuts, but as low as possible in saturated, hydrogenated, and trans fats. Likewise, the diet should be rich in complex carbohydrates, such as those provided by whole bread, legumes, and vegetables, but low in sugars and limited in pasta, rice, bread, fruit, and fruit juices, which are easily converted into sugars by the time they reach the intestine.
Be nourished. You can think of the human body as an army of cells always at war. The enemy includes oxygen and other molecules that damage DNA and cells; bacteria; and viruses, which are constantly trying to defeat the immune system. Like an army in need of rations, ammunition, and equipment, the body needs proteins, essential fatty acids (omega-3, omega-6), minerals, vitamins, and, yes, sufficient levels of sugar to fight the many battles raging inside and outside cells. When your intake of certain nutrients becomes too low, the body’s repair, replacement, and defense systems slow down or stop, allowing the damage to accumulate or fungi, bacteria, and viruses to proliferate. (The appendixes include a list of foods rich in each of the important nutrients, as well as sample weekly diets that meet established nutritional targets.) As extra insurance, take a multivitamin and mineral pill, plus an omega-3 fish oil soft gel every two or three days. Purchase these products only from reputable companies, where quality control ensures appropriate supplement content and stability.
Eat a variety of foods from your ancestry. To take in all the required nutrients, you need to eat a wide variety of foods, and it’s best to choose from foods that were common on your parents’, grandparents’, and great-grandparents’ table. This does not mean you should eat like your grandparents, but that within the guidelines of this book, you should pick foods your grandparents ate. The human body is the result of billions of years of evolution, and even the last one thousand years have helped filter out people not fit for a particular environment, or foods not appropriate for a particular genotype (the collection of all genes in a person). For example, in many northern European countries where milk was commonly consumed, intolerance to lactose (the sugar contained in milk) is relatively rare, whereas lactose intolerance is very common in southern European and Asian countries, where milk was not historically part of the traditional diet of adults. If a person of Japanese ancestry living in the United States suddenly decides to start drinking milk, which was probably rarely served at her grandparents’ table, she will likely start getting sick. Whether it’s lactose or kale, quinoa or turmeric (curcumin), you have to ask whether these were foods common at the table when you, your parents, or your grandparents were growing up. If not, it’s best to avoid them or consume them only occasionally. The potential problems are intolerances (for example, an inability to break down the lactose sugar in milk) or autoimmunities, such as the reaction to gluten-rich foods like bread and pasta observed in people with celiac disease. Although clear links have not been proved yet, it is possible that consumption of the wrong foods based on ancestry could be associated with many autoimmune disorders, including Crohn’s disease, colitis, and type 1 diabetes.
Eat twice a day plus a snack. Unless your waist circumference and body weight are in the normal or low range, it is best to eat breakfast and one major meal plus a nourishing low-calorie, low-sugar snack daily. If your weight or muscle mass is too low or if it’s dropping against your will, then eat three meals a day plus a snack. One of the major mistakes of guidelines on nutrition is blurring the line between what theoretically could work and what actually does work. We often hear that we should eat small meals five to six times a day. Aside from a lack of evidence supporting the benefit of such a regimen in terms of a long and healthy lifespan, it is extremely difficult for most people to regulate food intake when they are told to eat so often. Even if the meals contain 305 calories each, instead of the recommended 300 calories, that extra 30 calories a day, or more than 900 calories a month, means nearly 3 pounds of extra fat every year. Not surprisingly, over the past twenty years— the period when the six-meal diet was popular— America reached a record 70 percent portion of overweight and obese people. If you eat only two and a half meals a day, with only one major meal, it becomes much harder to overeat, particularly on a mostly plant-based diet. It would take large portions of fish, beans, and vegetables to get to the calorie level that would cause obesity. The high nourishment of the food, plus the volume of the meal, signals to your stomach and brain that you have had enough food.
In the elderly, this one major meal system may have to be broken down into two smaller meals to avoid digestion problems. Older people and adults prone to weight loss should stick to eating three meals a day plus one snack. For people trying to lose weight or those who tend to be heavy, the best nutritional advice is to eat breakfast daily; have lunch or dinner, but not both; and substitute for the missed meal one snack containing fewer than 100 calories and no more than 3 to 5 grams of sugar. (Do not skip breakfast, as this has been associated with increased risk for age-related diseases in multiple studies.) Which meal you skip depends on your lifestyle. The advantage to skipping lunch is more free time and more energy. On the other hand, there is the possible disadvantage of restless sleep from having consumed a large dinner, particularly for those who suffer from acid reflux. The disadvantage to skipping dinner is that it eliminates the most social meal of the day.
Observe time-restricted eating. Another common practice adopted by many centenarian groups is time-restricted eating, or confining all meals and snacks to within eleven to twelve hours or less a day. The efficiency of this method has been demonstrated in both animal and human studies. 6 Typically you would eat breakfast after 8 a.m. and finish dinner before 8 p.m. A shorter eating window (of ten hours or less) can be even more effective for weight loss, but it is much harder to maintain and may increase the risk of side effects, such as developing gallstones and possibly increasing the risk of cardiovascular disease. You should also not eat within three to four hours of going to sleep.
Practice periodic prolonged fasting: People under age sixty-five who are neither frail nor malnourished and are free of major diseases should undergo two periods of five days a year in which they consume a relatively high-calorie fasting-mimicking diet, or FMD. Most religious groups— including Muslims, Christians, Jews, and Buddhists— have practiced some form of fast, though some of these practices have been modified or abandoned over time. Muslims practice fasting during the month of Ramadan, but in modern times the daytime fast is often accompanied by overeating at night. During Lent, Christians used to undergo a month of severe calorie restriction ending in a week of fasting, but this practice, too, has largely been abandoned today. In chapter 6, I discuss the remarkable effects of five-day cycles of a fasting-mimicking diet on disease risk factors and the optimization of healthy longevity.
Follow the eight points above in such a way that you reach and maintain a healthy weight and abdominal circumference. In a longitudinal study of 359,000 European adults followed over ten years, high waist circumference and abdominal fat were associated with increased diabetes, hypertension, high cholesterol, and heart disease. Having a waist circumference of more than 40 inches in men and 35 inches in women doubled the risk of premature death, compared with having a waist circumference of less than 33 inches in men and 27 inches in women. Following the eight points above will allow you to reach and maintain low visceral fat, and a healthy weight and abdominal circumference.
For most people, the Longevity Diet can be adopted simply by replacing a limited number of items with foods that are just as enjoyable, if not more so. Virtually all diets fail because they are too extreme to maintain in the long run. They also fail because they require major changes to your habits and lifestyle. For example, many new diets require low carbohydrate intake, but carbohydrates are the food people around the world enjoy the most— whether it’s potatoes for northern Europeans, pasta for Italians and Americans, or rice for Asians. Thus, very low-carbohydrate diets, besides being associated with increased mortality and reduced lifespan, are not sustainable in the long run for most people. Because the Longevity Diet is closer to diets generally adopted by Americans, Europeans, and Asians, it can be embraced by people all over the world. In the following sections I explain how the above dietary recommendations are rooted in the Five Pillars of Longevity, since this is the key to understanding their effectiveness. I discuss studies of the laboratories I direct, as well as those of other laboratories and clinics.
Interestingly, Longo's "Five Pillars of Longevity" are sources of scientific knowledge, not substantive recommendations.