It has previously been found that limiting meat consumption could lead to better overall health. But studies on the subject tend to have certain limitations, often linked to genetics or lifestyle.

This is why researchers at Stanford Medicine, the medical school of Stanford University in the United States, decided to evaluate the effects of a vegan diet on identical twins, who grew up in the same household with similar lifestyles.

Twenty-two pairs of twins were included in the study, conducted between May and July last year, in which one twin was assigned a vegan diet, and the other an omnivore diet.

Both diets were considered healthy, being rich in vegetables, legumes, fruit and wholegrains, and free from refined sugars and starches. The vegan diet was based solely on plant-based products, while the omnivore diet included chicken, fish, eggs, cheese and dairy.

Participants received delivered meals for the first four weeks – for breakfast, lunch and dinner – and then prepared their own meals for the following four weeks of the study. Each individual also kept a diary listing the foods they had eaten.

Published in the journal Jama Network Open, the findings suggest that a vegan diet has the potential to improve heart health in just eight weeks. Indeed, more improvements were observed in the first four weeks following the change of diet.

The researchers also report that the vegan participants had lower levels of low-density lipoprotein cholesterol (the “bad” kind), insulin and body weight than the omnivorous participants – markers that scientists associate with better cardiovascular health.

“Based on these results and thinking about longevity, most of us would benefit from going to a more plant-based diet,” senior author Christopher Gardner observed.

The aim of this research is not to force people to adopt a 100% vegan diet, as the scientists are aware of the difficulties and upheaval this could represent. Rather, the goal is to encourage people to limit meat consumption and turn to plant-based alternatives.

“What’s more important than going strictly vegan is including more plant-based foods into your diet. Luckily, having fun with vegan multicultural foods like Indian masala, Asian stir-fry, and African lentil-based dishes can be a great first step,” Gardner added.

Previous research has compared the Mediterranean and vegan diets, both of which are considered beneficial to health, although researchers identified greater benefits with the latter. Other studies have even looked at the impact of a vegan diet on dogs and cats, revealing that four-legged vegans were healthier.