Ian Rowland: “If you want to change the world, start on your plate. The diet of the future is plant-based”

There is a daily gesture that can impact health, the environment and even the future of preventive medicine: deciding what to put on your plate. This is where the food revolution that is now under the spotlight of researchers, doctors and governments starts: the plant-based diet, or a diet based mainly on foods of plant origin.

It doesn't necessarily mean eliminating animal products altogether, but prioritizing fruits, vegetables, legumes, whole grains, nuts and seeds, while minimizing (or avoiding) meat, dairy, eggs and ultra-processed foods. To better understand what the plant-based diet is, why it is so beneficial for our health and how to follow it in everyday life in a simple way, during an international event organized at the Danone Global Research & Innovation Center in Paris-Saclay, we interviewed Professor Ian Rowland , Professor of Human Nutrition at Reading University, one of the leading researchers on the impact of plant-based nutrition and phytochemicals on health, particularly on the prevention of cancer and cardiovascular disease.

Vegans, Vegetarians, Flexitarians: What Does Plant-Based Really Mean?

Plant-based foods are becoming increasingly popular, as more people are concerned about their personal health and that of the planet. According to the latest data from market research company Circana analyzed by the non-profit think tank The Good Food Institute Europe, in Italy alone, in 2024 the plant-based foods market reached 639 million euros, recording a +16.4% compared to 2022 and a +7.6% on 2023.

But what distinguishes the plant-based diet from the vegan or vegetarian one? “The vegan diet is more rigid. It excludes all animal products and those of animal origin such as meat, fish, dairy products, eggs, honey. It is often an ethical choice as well as a nutritional one, linked to the protection of animals and the environment”, replies Rowland who adds: “The vegetarian diet excludes meat and fish, but generally includes dairy products and eggs. It is therefore less restrictive than the vegan diet, but less flexible than the plant-based one. The latter is also called a flexitarian diet and is based on plant-based foods, but does not completely exclude animal products. Those who follow a plant-based diet can occasionally consume meat, fish, dairy products or eggs, but favor fresh and minimally processed foods”.

More vegetables, less disease

So, the plant-based diet is a middle ground, designed to maximize the benefits of plant-based nutrition without requiring absolute sacrifices. It is increasingly appreciated for its positive effects on health, prevention of chronic diseases and environmental impact. “Unfortunately, diseases related to often incorrect diets, such as type 2 diabetes, cardiovascular disease and obesity, are constantly increasing. But today there is a lot of evidence to support this dietary model. Prospective studies on Mediterranean, vegetarian and flexitarian diets show a clear association between high consumption of vegetables and reduced risk of cardiovascular disease, cancer, type 2 diabetes and general mortality”, underlines the expert. But it is not just observation. “There are also very solid intervention studies,” explains Rowland, “that show causal relationships: when you switch from an omnivorous diet to a more plant-based one, you observe improvements in cholesterol levels and blood pressure”.

The study on Nature on liver health

Just recently, a study published in the journal Nature , conducted on over 8,500 adults, assessed the impact of plant-based diets on liver health, particularly on steatosis and fibrosis. Researchers at the University of Medical Sciences in Kermanshah (Iran) used validated clinical indices to estimate the presence of liver damage and observed that greater adherence to diets rich in whole plant foods is associated with a lower risk of liver fibrosis. On the contrary, a significant reduction in steatosis did not emerge, especially in participants with a high intake of fructose, which is instead correlated with an increased risk. The data suggest that, to promote liver health, it is important to favor unrefined plant foods, rich in fiber and low in simple sugars, avoiding industrial plant-based products and rich in fructose.

Nutrition as a prevention strategy

Therefore, what we bring to the table has a real therapeutic function, indeed a preventive one. "From the point of view of prevention - Rowland underlines - there is very strong evidence that the more vegetables we put in our diet, the more health benefits we get. But a balanced plant-based diet can also support recovery from an illness, improve immune function and reduce the risk of relapses. Good nutrition is an integral part of therapy, even when it does not replace drugs". Among other things, the flexitarian diet is gaining more and more followers in Italy too.

A recent survey by AstraRicerche conducted in June 2025 on over a thousand people between the ages of 18 and 70, indicates a transition towards more plant-based diets, with a predicted decrease in omnivorous diets and an increase in flexitarian and vegetarian diets.

Foods of a plant-based diet

But what exactly does a plant-based diet include? “A wide range of foods. First of all, vegetables and fruit are the absolute protagonists. Seasonal vegetables - from broccoli to spinach, from courgettes to tomatoes - are consumed every day, raw or cooked, as the basis of main dishes or nutritious side dishes. Fruit is also abundant, both fresh and dried, useful for breakfast, snacks or natural desserts”, replies the nutritionist. Another fundamental component is whole grains, such as brown rice, oats, spelt, quinoa, barley or whole wheat bread and pasta. They provide slow-release energy and help keep blood sugar levels stable. These are joined by legumes - lentils, chickpeas, beans, peas - which represent the main source of plant-based proteins. When combined with cereals, they offer a complete amino acid profile, useful for supporting the body's functions. Dried fruit and oil seeds, such as walnuts, almonds, flax seeds or chia seeds, rich in unsaturated fats, fibre and micronutrients, cannot be missing. “Vegetable fats, such as extra virgin olive oil or avocado, are also used daily to season or enrich meals in a healthy way. Plant-based alternatives to dairy products are also increasingly popular, such as soy, oat, almond or coconut milk and yogurt, preferably fortified with calcium, vitamin D and B12,” adds Rowland.

Variety and taste

The plant-based diet does not lack flavor and variety. Spices, herbs, garlic, onion, lemon and vinegar are used to enhance flavors and increase nutritional value. In general, fresh, minimally processed and naturally nutrient-rich foods are preferred. What is limited or excluded – depending on personal choices – are meat, fish, dairy products, eggs and all animal products. But refined sugars, industrial snacks and ultra-processed foods are also reduced to a minimum.

How to avoid possible deficiencies

It is known that those who follow a vegetarian or vegan diet can encounter some nutritional deficiencies if the diet is not well planned. “Vitamin B12 is the most common deficiency in vegans, since it is absent in plant foods, and must be taken through supplements or fortified foods. Iron, calcium, zinc, iodine, omega-3 and vitamin D can also be insufficient, especially if foods of animal origin are completely excluded,” explains the nutritionist who, however, specifies: "Vegans are usually much more careful about their diet, because they are aware of possible micronutrient deficiencies, but they are also very proactive in preventing them, through supplements or fortified foods”.

A balanced plant-based diet can be nutritionally complete, but it requires attention, variety and, in some cases, targeted supplementation. “The risk is when you follow a flexitarian ‘do-it-yourself’ diet without realizing possible imbalances: for example, we know that 90% of adults in Europe do not consume the recommended daily amount of fiber”.

The various levels of industrial food processing

Another sticking point is the classification of ultra-processed foods. “The concept of ultra-processed comes from the Nova system, which classifies foods from unprocessed to ultra-processed into four categories,” Rowland explains. The Nova system classifies foods based on their level of industrial processing, dividing them into four groups: unprocessed or minimally processed foods (such as fruits, vegetables and legumes), processed culinary ingredients (such as sugar and oils), processed foods (such as bread and cheese) and ultra-processed. The latter are highly industrialized products, often high in additives, sugar, fat and salt, and designed to be ready to eat. There is growing scientific evidence that a high intake of ultra-processed foods is associated with an increased risk of obesity, type 2 diabetes and cardiovascular disease, regardless of caloric or nutrient content.

Don't demonize them, but read the labels

Nova is increasingly being used in public health studies to assess overall diet quality. “But it’s not the degree of processing itself that matters, it’s what’s in those foods,” Rowland says, adding: “A lot of ultra-processed foods are high in saturated fat, sugar, and salt, and yes, they can be harmful to your health. But there are also ultra-processed foods that are high in fiber, low in sugar, low in saturated fat, and therefore have a positive impact.” The key, Rowland says, is to read the label carefully and not just take the superficial label.

The new Italian food pyramid and the role of legumes

The new Italian food pyramid recently presented by the Italian Society of Human Nutrition also seems to fit perfectly with the plant-based diet trend. It favors vegetable proteins from legumes over those from meat, placing them on the same level as fish and fresh cheeses, while relegating red and processed meats to the top of the pyramid, where they are consumed only occasionally, together with sweets. Therefore, the new Italian food pyramid classifies legumes as primary protein sources, whereas previously they were considered less noble protein sources. "This is a significant change. In the past, legumes were considered second-rate proteins, because they do not contain all the essential amino acids. But today we know that it is sufficient to combine them with other plant foods to obtain complete proteins", comments Rowland. An example? "In the UK we often eat baked beans on toast: on their own they are not complete proteins, but together they become complete proteins". And then there is the environmental aspect: "The planet cannot sustain the current level of meat consumption. It takes enormous amounts of resources to produce foods of animal origin". Rowland's conclusion is clear: "A healthy diet is also a sustainable diet. Human health and the health of the planet go hand in hand."