By Amy Culliford
It’s been over a decade since the Food and Agriculture Organisation defined the term “sustainable diets”. Since then, many scientific publications and reports by international organisations have stressed the significant environmental and ethical impacts of animal agriculture as well as the negative health impacts of excessive meat and dairy consumption. This includes the ground-breaking Eat-Lancet Commission report, setting out the planetary health diet which has become the “gold standard” in the field of healthy sustainable diets.
Have we agreed what a plant-based diet looks like?
The idea that we need to reduce meat and dairy consumption has been steadily gaining traction internationally. Although it is recognized that one can achieve all the nutrients needed on a diet with no animal foods many are relieved to know that it is not necessary to eliminate all animal-based foods to benefit the health of people and planet. The term plant-based diet encompasses a range of dietary patterns, from vegan diets to flexitarian diets which include modest amounts of animal-based foods.
There is no one-size-fits-all diet but the consistent message is that we need to eat more plants and less animal-sourced foods.
The UK national dietary guidelines, the Eatwell Guide, is one example of a plant-based diet made up mostly of fruits, vegetables, wholegrains and starchy carbohydrates with a balance of dairy or plant-based milk alternatives, pulses, beans, meat, eggs and fish. In May 2023, the WWF published their report Eating for Net Zero setting out a healthy, sustainable and socially acceptable diet for the UK population, recommending further reductions in meat and dairy as well as higher standards of farming with less reliance on chemicals and better animal welfare.
Are we nearly there in achieving recommendations?
The short answer is that no, we still have a long way to go. A 2020 study found that those who meet five of the nine Eatwell Guide recommendations have a 30% lower carbon footprint and a 7% lower mortality rate, yet this is only one third of the UK . Reynolds et al modelled affordable, healthy sustainable diets for different income groups. All were able to achieve nutritional recommendations whilst reducing dietary carbon footprint by almost 60%, however this required substantial change from current diets.
The bottom line is that most of us are still eating too much meat and sugary, fatty processed foods but not enough plants. Still, we are seeing a growing interest in plant-based diets in the UK. According to a recent YouGov survey, 25% of the UK population now identify as either vegan, vegetarian, pescetarian or flexitarian, up from 23% in 2019. In the 2022 Eating Better survey a quarter of Brits reported eating less meat than the previous year and 61% said they would be willing to eat less meat.
What is the role of plant-based alternatives?
The food industry has responded to this plant-based popularity by developing alternatives to nearly every animal-based food we can imagine. New technologies are making plant-based meat, dairy, seafood and eggs more competitive in taste, texture and price than ever before. The European plant-based alternative market boomed in the last few years reaching a massive €5.8 billion. In the UK, the percentage of people consuming plant-based alternatives almost doubled between 2008 and 2019 (from 6.7% to 13.1% of the population).
On one hand this removes barriers to adopting plant-based eating, such as taste preferences and a lack of time and skills for cooking. But do these foods offer the same nutritional and environmental benefits as more traditional plant-based foods such as fruits, vegetables, wholegrains and pulses? Or are we just heading in the same direction of cheap, convenient but nutrient-devoid foods, only this time with a plant-based label?
The answer is, it depends! Plant-based alternatives can be a convenient and nutritious switch for anyone wanting to reduce or eliminate animal-based foods from their diet. However, not all products are created equal. Alongside more traditional alternatives to meat and dairy, we are seeing a boom in plant-based convenience foods such as ice-cream, pizza, and ready meals.
Research into the health and environmental impacts of these novel products is limited as most studies have focused on whole plant-based foods for their analysis. With new products constantly emerging into the market, policy makers, manufacturers and consumers alike need to stay on their toes to avoid spiralling in the wrong direction.
Is there space for plant-based “junk foods”?
As researcher Jennie Macdiarmid emphasised, we can’t assume that a plant-based label automatically makes a food good for us and the planet. Many plant-based convenience foods have a better nutrient profile and lower environmental impact compared with the conventional products they replace. However, there are also plenty of products on the market which are even higher in salt, fat or sugar and are lacking in other key nutrients. Either way, a diet packed with heavily processed plant-based foods is certainly not aligned with sustainable healthy dietary guidelines.
Whether there is any place for HFSS foods in a balanced diet, plant-based or not, is an ongoing debate. The current consensus is that they should be considered an occasional treat but not part of the daily diet, hence placing them outside of the main Eatwell plate. There is space for plant-based “junk foods” but we should continue to promote a diet of mostly whole, unprocessed plant-based staples and educate manufacturers and consumers alike on the importance of producing and choosing healthier plant-based alternatives.
Could fortification of plant-based alternatives be the answer?
Whilst we can certainly meet all of our nutritional needs via a well-balanced plant-based diet regular consumption of fortified foods and/or supplements is recommended for those who chose a fully vegetarian or vegan diet. Fortification of plant-based alternatives with key nutrients can facilitate the much-needed transition to more sustainable and nutritionally adequate diets. However, currently there is huge variability in the nutritional profile of these products.
Going forward, we need to see clearer guidance for manufacturers around fortification. Efforts have been made in the US to propose nutrient standards for plant-based milks, to ensure they are similar to dairy milk in terms of energy and protein content as well as levels of calcium, vitamins A, D, B2, and B12. However, further research is needed to clarify the role of these products in the diet and therefore which nutrients should be added, based on the needs of the population.
We also know that it’s important to move away from focusing on the nutrient content of specific foods and instead focus on the nutritional adequacy of the dietary pattern as a whole. As an example, the majority of UK adults consume well above the RNI for protein (0.75kg per kg body weight) and a modelling study of the “Eatwell diet” recommended a 24% decrease in protein intakes. Therefore, adding by protein to plant-based alternatives we may be missing an opportunity to achieve this recommendation.
We also shouldn’t forget that an omnivorous diet is also not necessarily a healthy diet. Deficiencies can and do occur in both plant-based dieters and meat-eaters alike. Overall diet quality and variety is important, no matter which diet we choose.
Can we really get everything we need from plants?
Researchers have proposed a Planetary Health Diet Index, based on the EAT-Lancet planetary health diet recommendations. A higher score on the index was associated with better dietary quality (in terms of nutrient intake) as well as lower carbon footprint. A clinical study of almost 100,000 French adults also found that greater adherence to the EAT-Lancet planetary health diet improved nutrient intakes.
However, there has been a recent criticism of the planetary health diet, suggesting that strict adherence to the diet may lead to deficiencies in iron, zinc, calcium and vitamin B12, particularly for women of reproductive age. The authors of this critique proposed a modified version of the diet with a higher proportion of animal-based foods (still lower than current consumption) and fewer high-phytate foods such as legumes and wholegrains, due to their potential to affect absorption of these minerals.
Springmann, who was part of the original EAT-Lancet commission, has since rebutted the study, highlighting that the modified diet could lead to an additional 1 million diet-related deaths per year compared with the planetary health diet. He also estimates that, if adopted globally, the diet would result in higher diet-related greenhouse gas emissions and land use than current diets and could double the food budget in low-income countries. The fact remains that global guidelines such as the planetary health diet are a baseline, intended to be adapted to suit national public health needs and local food culture and availability, as with the Danish adapted plant-based diet.
How can we facilitate the shift towards plant-based diets?
The Behavioural Insights Team report, A Menu for Change, offers evidence-based strategies rooted in behavioural science to drive the much-needed shift towards sustainable diets. The report sets out 12 recommendations for government, industry and civil society (including the public) to make sustainable food the easy, appealing, and normal choice. Suggestions include eco-labelling, taxes on high environmental impact foods, increasing availability and promotion of plant-based options in retail and hospitality and marketing them as a delicious, aspirational choice.
One absolutely necessary component of several recommendations is effective communication, which we dived deeper into in our recent scientific publication. As well as clear, consistent guidance on sustainable healthy diets, we need creative engaging campaigns that target and engage different population groups. This must be bolstered by policy to create a supportive food environment and a food system which makes the wellbeing of people, planet and animals a priority, as set out in Henry Dimbleby’s National Food Strategy.
Facilitating the shift towards a more sustainable food system needs collaboration across multiple levels Consistent and collective effort is needed to achieve a plant-based way of living.
Guidelines, surveys and key reports
Sustainable Diets and Biodiversity (2010). Food and Agriculture Organisation
Healthy Diets from Sustainable Food Systems (2019). EAT-Lancet commission
The Eatwell Guide (2016). Public Health England
Eating for Net Zero (2023). World Wildlife Federation
Dietary choices of Brits (2023). YouGov Survey
Cost and choice are key to sustainable eating finds 2022 public poll from Eating Better (2022). Eating Better
National Food Strategy Independent Review (2021). Dimbleby et al.
A Menu for Change (2020). Behavioural Insights Team
Health Impacts and Environmental Footprints of Diets That Meet the Eatwell Guide Recommendations: Analyses of Multiple UK Studies (2020). Scheelbeek et al. BMJ Open
Healthy and sustainable diets that meet greenhouse gas emission reduction targets and are affordable for different income groups in the UK (2019). Reynolds et al. Public Health Nutrition
The role of plant-based alternative foods in sustainable and healthy food systems: Consumption trends in the UK (2022). Alae-Carew et al. Science of The Total Environment
The food system and climate change: are plant-based diets becoming unhealthy and less environmentally sustainable? (2021). MacDiarmid. Proceedings of the Nutrition Society
Plant-based animal product alternatives are healthier and more environmentally sustainable than animal products (2022). Bryant. Future Foods
The Safe and Effective Use of Plant-Based Diets with Guidelines for Health Professionals (2021). Craig et al. Nutrients
The Potential of Food Fortification as an Enabler of More Environmentally Sustainable, Nutritionally Adequate Diets (2023). Grasso et al. Nutrients
International Analysis of the Nutritional Content and a Review of Health Benefits of Non-Dairy Plant-Based Beverages (2021). Craig & Fresán. Nutrients
Proposed Nutrient Standards for Plant-Based Beverages Intended as Milk Alternatives (2021). Drewnowski et al. Frontiers in Nutrition
Eatwell Guide: modelling the dietary and cost implications of incorporating new sugar and fibre guidelines (2016). Scarborough et al. BMJ Open
Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review (2022). Neufingerl et al. Nutrients
Development and Validation of an Index Based on EAT-Lancet Recommendations: The Planetary Health Diet Index (2021). Cacau et al. Nutrients
Estimated micronutrient shortfalls of the EAT–Lancet planetary health diet (2023). Beal et al. The Lancet
Development of a Danish Adapted Healthy Plant-Based Diet Based on the EAT-Lancet Reference Diet. Lassen et al. Nutrients
Improving Communication of the UK Sustainable Healthy Dietary Guidelines the Eatwell Guide: A Rapid Review (2023). Culliford, Bradbury & Medici. Sustainability