An ideal diet is generally very difficult to define. First, the majority of nutritional evidence is based on observational studies, from which it is remarkably difficult to assess the independent effect of diet on health. Second, diets are very difficult to study in randomized trials, as there are many variables and follow-up periods would need to be extensive to capture meaningful effects. Third, the optimal diet is also an individual matter, influenced by factors such as age, sex, disease profile, and the local availability of fresh ingredients.

The best available evidence comes from a few large intervention trials on the Mediterranean diet, genetic analyses, and mechanistic studies. Be skeptical of any nutritional claims that sound overly precise.

Foundation

Mediterranean-style diet is the most extensively studied dietary pattern for cardiovascular health. It is rich in vegetables, legumes, whole grains, fish, nuts, and olive oil. It is also worth noting that some of the benefits of the traditional Mediterranean diet may not be explained by individual foods alone, but by the fact that the ingredients were locally produced, minimally processed, fresh, high in nutrient density, and more diverse in their microbial content. A diet built on the same principles including locally grown or home-grown food can produce largely the same benefit.

Adequate protein intake. Target 1.5–2.2 g/kg/day. Protein is the most important macronutrient for preserving muscle mass. Animal-derived protein generally has a higher biological value and a more complete amino acid profile than plant proteins, which is particularly relevant when total intake is low. A vegetarian diet can meet protein needs, but it requires more planning. Soy has the most complete amino acid profile among plant proteins. Supplement with whey protein mixed into water around training sessions, porridge, or smoothies as needed.

Minimizing ultra-processed foods. Consumption is consistently associated with cardiovascular disease, type 2 diabetes, depression, and all-cause mortality. Controlled trials have shown that a diet containing ultra-processed products leads to significantly higher energy intake. These products are engineered to drive overconsumption, containing large amounts of refined carbohydrates, seed oils, salt, and sugar in combinations that bypass satiety signals. Additionally, they contain little fiber and essential nutrients, and many of them include emulsifiers and additives that may disrupt gut mucosal integrity and microbiome composition.

Fiber quantity and diversity. Target 25–30 grams per day from diverse sources: vegetables, fruits, legumes, whole grains, nuts, and seeds. Different fiber types feed different microbial populations, so varying fiber sources supports a more diverse gut microbiome, which is consistently associated with better metabolic and immune health. A practical goal is at least 30 different plant-based foods per week.

Salt. High salt intake is common (over 5 g/day) and raises blood pressure, particularly in salt-sensitive individuals. Moderate restriction is justified at the population level, but a very low-salt diet is not appropriate for everyone. For example, athletes who sweat heavily need adequate salt intake for performance and fluid balance.

Fermented and microbe-rich foods. Yogurt, kefir, sauerkraut, kimchi, and other naturally fermented foods deliver live microbes and their metabolites to the gut. Regular consumption is associated with increased microbiome diversity and decreased systemic inflammation based on current evidence.

Home gardening. Home-grown vegetables and herbs expose you to soil microbiota that store-bought produce does not provide, as microbes often have to be eliminated to improve shelf life for transport and storage. Our immune system evolved in close contact with environmental microbes, and the modern food supply chain has radically reduced this exposure. Gardening also practically increases vegetable consumption and physical activity, and is typical of centenarian populations. Consider at least an herb box on a balcony or a raised bed in the yard.

Other practical considerations

Meal timing. Insulin sensitivity follows a circadian rhythm: glucose tolerance is at its best in the morning and during the day, and a meal eaten late in the evening raises blood sugar more than an equivalent meal during the day. A regular meal rhythm supports the energy intake needed for training, recovery, and cognitive performance.

Time-restricted eating. Limiting eating to a specific time window can be a tool for managing total energy intake, but randomized trials do not show it produces additional benefit beyond caloric restriction alone. It may be considered on an individual basis as one tool among many.

Walking after meals. Approximately 10–15 minutes of walking significantly blunts postprandial glucose and triglyceride spikes.

Excessive fructose intake. Free fructose in large quantities, primarily from soft drinks and added sugar, independently promotes hepatic fat accumulation, causing metabolic problems. The fiber in a whole fruit and its smaller total fructose dose make it a metabolically different entity compared to juice.

Coffee. Approximately three cups per day is associated with lower all-cause mortality and cardiovascular risk. Filtered coffee is clearly a better option than unfiltered coffee (boiled coffee, French press), which raises LDL cholesterol. Caffeine intake should be limited to the morning and early afternoon to avoid sleep disruption. Caffeine is eliminated from the body slowly.

Heavy metals in food. Certain foods accumulate heavy metals, which is worth being aware of. Brown rice accumulates arsenic. Large predatory fish (tuna, pike) accumulate mercury. Cocoa and chocolate may contain cadmium and lead. These are not reasons to avoid these foods entirely but to rotate sources: cycle grain types, favor smaller fish species more often, and avoid excessive reliance on any single food.

Individuality is what matters

There is no single optimal diet and meal schedule that suits everyone. Metabolic responses to the same foods vary between individuals, influenced by genetics, gut microbiome composition, insulin sensitivity, physical activity level, and health status. The foundation described above applies broadly, but the details should be tailored. For some individuals, a lower-carbohydrate diet may be a better option, such as in insulin resistance, type 2 diabetes, or epilepsy. Women’s body fat percentage should be higher than men’s to maintain normal hormonal function. Investing in supporting a diverse gut microbiome is particularly sensible after antibiotic courses. Protein intake is more critical for older adults and those engaged in resistance training.

Continuous monitoring. A few weeks of continuous glucose monitoring can be an illustrative experience. It builds an understanding of which foods, combinations, portion sizes, and timing affect your blood sugar.