The Paper of the Month for September is ‘The food system and climate change: are plant-based diets becoming unhealthy and less environmentally sustainable?’ and the blog is written by author Jennie. I. Macdiarmid and is published by Proceedings of the Nutrition Society and is free to access for 1 month.

We need to act now to limit increasing global temperatures by reducing greenhouse gas emissions to meet global targets set out in the Paris Agreement. Among other things, this means changing our diets and reducing our consumption of meat and dairy since livestock production has the highest environmental impact in the food system. Hence, the need to transition away from diets high in animal products to more plant-based diets. Nutritionally balanced plant-based diets, which can include small amounts of meat and dairy, can also have health benefits. However, that not all plant-based diets are necessarily healthy, despite the halo effect associated with health and environmental sustainability that surrounds the term plant-based foods.

Awareness about reducing meat consumption to help tackle climate change has increased with publication of reports from high level committees, such as the Intergovernmental Panel on Climate Change, and greater media coverage over the past few years. The food industry has responded with an explosion in the market of the plant-based meat alternatives, from non-dairy milk to meat-free burgers and sausage rolls. Alongside these are numerous meat-free processed convenience food, including ready to eat meals. This helps address some of the concerns people expressed about it being difficult and time consuming to prepare meat-free meals. However, many are high in salt, fat and sugar making them less healthy.

Plant-based diets can be categories into traditional and modern-day diets. Traditional plant-based diets are associated with health benefits and lower greenhouse gas comprising plenty of wholegrains, pulses, fruit and vegetables. However, this new market of plant-based alternatives is creating very different diets, ones that could be called modern-day plant-based diets, which are not as healthy or environmentally sustainable. They comprise highly processed plant-based alternatives many with high in salt, fat and sugar contents. Further, some of the ingredients are derived from monocrops such as palm oil, corn and soya, which have reduce biodiversity and are linked to deforestation. These types of diets are more likely to be adopted by younger groups in populations and those adopting vegetarian diets more recently.

Changes need to be made to our diets for both human and planetary health. However, plant-based alternatives can help the transition to reduce meat consumption, but it cannot be assumed the name ‘plant-based’ always means healthy. There is momentum building to eat less meat, especially with the increasing number of these alternatives, but we need to make sure unhealthy plant-based foods do not derail the progress to achieve healthy and sustainable diets. The public and industry both have a role to play.

Each month a paper is selected by one of the Editors of the five Nutrition Society Publications (British Journal of Nutrition, Public Health Nutrition, Nutrition Research Reviews, Proceedings of the Nutrition Society and Journal of Nutritional Science). Take a look at the entire Nutrition Society Paper of the Month Collection.