Look at the communities in the world with the longest life expectancies and one of the key things they share is a mainly plant-based diet with plenty of fruit and vegetables. Skewing your diet towards plants seems to protect against many age-related conditions, including heart disease, cancer, obesity, and type 2 diabetes.
Studies show that diets based mainly on plants are linked to a reduction in mortality, and from cardiovascular disease especially. And you don’t need to be 100 per cent vegetarian to benefit: a 2015 study found that diets comprising 70 per cent plant-based foods cut the risk of cardiovascular disease by 20 per cent, so the priority is to obtain most nutrients from plants.
Good intakes of fruit and vegetables seem to help lower the risk of many other conditions, too, such as respiratory problems, dementia, arthritis, and age-related macular degeneration. Such emphasis is core to the longevity eating plan.
Experts agree the health benefits of plant-based diets are twofold. First, by eating more plant foods we “crowd out” animal foods and reduce our intake of the nutrients they contain that are linked to poorer health. Second, most plant-based foods come with in-built beneficial nutrients, many of which are unique to plants.
Only plants contain fibre, which plays an important role in keeping us full and regular. When we eat fibre-rich foods we are less likely to overeat, making it easier to stay a healthy weight. And fibre also has body-wide benefits relating to heart disease, bowel complaints, and certain cancers (see below).
24%
reduced risk of heart disease from eating 800g (13⁄4lb) fruit and veg a day.
Fibre isn’t the only nutrient unique to plants; they’re also rich in naturally occurring chemicals known as phytochemicals, many of which act as antioxidants and help prevent inflammation. In lab studies, phytochemicals have been linked to everything from boosting immunity and slowing down or stopping the growth of cancer cells, to delaying cognitive decline and helping to lower cholesterol. For a detailed look at phytochemicals.
Studies suggest it’s the unique, overall package of nutrients in plant foods that protects health. When vitamins or antioxidant compounds are consumed in isolation they often don’t offer the same benefits, and may even be harmful in some cases: vitamin E and beta-carotene supplements, for example, may have been found to increase the risk of certain cancers. Ultimately, most experts agree it is better to gain plant-derived nutrients from plants themselves.
Is five-a-day enough?
The World Health Organization recommends eating 400g (14oz) of fruit and vegetables a day, or roughly five portions. A 2017 study found that every 200g (7oz) increase in fruit and veg offered health benefits, and that 800g (13⁄4lb) a day – about 10 portions – was the optimal intake. That said, 10 portions has been criticised as unrealistic, so aim for five but more is better.
Fibre can only be obtained from plants, so a plant-based diet will naturally be high in fibre. Fibre cannot be digested by the body; it comes as two main types: soluble and insoluble. Soluble fibre forms a gel in the intestine and helps control blood sugar, while insoluble fibre increases the bulkiness and softness of stools. Find out how fibre benefits health and longevity, below.
