Eating for the planet as well as for our own health can be tricky. On the one hand we want to choose more sustainable foods that have less impact on the environment; on the other hand, we don’t want to miss out on those healthy nutrients that can come from foods that are less kind to the planet. What to do?
Scientists believe they’ve come up with an answer to this conundrum. They’ve developed a diet model that may help switch to a more plant-based diet which is both healthy and environmentally friendly, while taking into account what we’re used to eating. The diet model sets out stepwise reductions in the amount of meat to eat, while substituting it with nutrients provided by other foods including fruit, vegetables, wholegrains, and dairy products (1).
And the good news is that even small changes can go a long way to putting us on track for a better future.
Plant-based diets are the way to go for a sustainable future
Diets that include mainly plant-based foods are associated with long-term health and environmental benefits. Plant-based diets are generally more nutritious than meat-based diets, containing less potentially harmful saturated fatty acids and sodium, especially in the case of processed meat. Their production also has a lower impact on environmental resources than meat production, making plant-based foods a more sustainable food source.
But meat is an important source of protein and essential amino acids, minerals, and vitamins, including iron, zinc and some B-vitamins that can be difficult to get from plants. So, maintaining a healthy level of these nutrients may become challenging for people aiming to cut down on their meat.
How can we safely and sustainably reduce our meat consumption?
To help answer this question, scientists created a mathematical model that gradually reduces meat consumption while maintaining healthy, nutritious eating. Starting with the typical French adult consumption, they used modelling to reduce meat in successive 10% steps, each stage being designed (1).
Each step of the diet model included more fruits, vegetables, and wholegrains but less meat, soft drinks, and refined grain products such as white bread, pasta, and rice. As meat consumption was reduced, levels of other animal-sourced foods – seafood, dairy, and eggs – were maintained or increased to keep a healthy balance of nutrients. They played an increasing role in the intake of some nutrients such as iron and zinc, vitamins A and B12, and iodine as the diet plan progressed.
The researchers discovered that the earliest steps of this diet model had the biggest impact on healthy, sustainable eating. Early steps included cutting out red and processed meats in favour of poultry, alongside a rapid increase in fruit, vegetable, and wholegrain consumption.
‘This study demonstrates that it is possible to reduce the share of meat in the diet, and even remove it totally, without jeopardizing nutrient security (provided that the diets are properly structured).’ – Dussiot A, et al, 2022
During the later steps of this diet model, poultry was the only meat remaining and its further reduction had a smaller impact on healthy, sustainable eating. Some nutrients were limiting, in particular iron, zinc, and vitamin A, but sufficient levels were achieved by restructuring diets based on food groups other than meat.
Three steps towards healthy meat reduction
The stages modelled by the researchers can be summarised as follows:
- Swap red and processed meats for poultry and refined grain products for wholegrains; cut down on soft drinks
- Gradually cut down on poultry, substituting seafood, eggs, and dairy products, as well as eating more fruits, vegetables, and wholegrains
- Cut out meat altogether, maintaining high levels of fruits, vegetables, wholegrains, and including dairy products, seafood and eggs.
What role can meat substitutes play in a healthy, sustainable diet?
Another way of curbing our meaty meals is to switch to plant-based meat substitutes. Designed to look and taste the same as meat products, these mimics are growing in popularity. Products such as plant-burgers and plant-based sausages are not just intended for vegetarians but for everyone wanting to eat less meat. And meat substitutes can easily be incorporated into a flexitarian diet – plant-based with small amounts of meat and modest intake of dairy and other animal-sourced foods – known to be a healthy and sustainable choice.
In particular, meat substitutes can be a great solution for those of us in Western countries, where meat is part and parcel of our daily dining and it’s not so easy simply to drop it from the menu. Swapping it for plant-based meat substitutes is an attractive option because they can be used in the same way as meat and don’t need any big changes to meal planning.
Meat substitutes come with a host of different ingredients, including soy, wheat, or pea proteins and all kinds of pulses, cereals, vegetables, herbs, and spices. But as yet, little is known about the optimal composition of a meat substitute to maximise overall diet quality and nutrition.
So, scientists have sought to develop meat substitute option that addresses this challenge. They’ve studied how different meat substitutes can change the quality of people’s diets and come up with the best ingredients for a meat substitute to improve nutrition. Using computer models, they designed a meat substitute that was entirely plant-based and composed of minimally processed ingredients (2).
Example of a plant-based meat substitute designed to maximise nutritional composition
- 47% pulses – contributing to iron content
- 18% cooked vegetables – source of vitamin C
- 15% cereals – contributing to iron content
- 5% nuts and seeds – source of omega-3 essential fatty acids
- 5% dried fruits and vegetables – source of B-vitamins
- 5% vegetable oils – source of omega-3 and omega-6 essential fatty acids
- 4% starch – contributing to carbohydrate content
- 1% herbs, spices, and salts – contributing to calcium and iron content
This optimised meat substitute was high in protein, low in saturated fatty acids, rich in fibre, and more nutritious overall than the meat it substituted. The researchers found it provided high levels of some nutrients that are often lacking from meat-based diets, such as omega-3 and omega-6 essential fatty acids, folate, and vitamin C. It also provided lower levels of saturated fatty acids and sodium than meat.
The meat substitute provided plenty of most essential nutrients that we normally get from meat, including vitamin B6, potassium, iron. However, it could not completely compensate for ideal levels of zinc and vitamin B12. So the search is still on for healthy and sustainable options and future research could investigate further solutions, based on different ingredients, that aim for optimal nutritional and environmental outcomes.
‘Choosing the correct ingredients can result in a nutritionally highly effective meat substitute that could compensate for reductions in many nutrients supplied by meat while providing key nutrients that are currently insufficiently consumed.’ – Salomé M, et al, 2022
So, how can we ensure that low-meat diets provide enough nutrients?
Previous studies have shown that fortifying meat substitutes could help to maintain adequate intakes of vitamin B12, zinc, and iron (3,4). Some plant-based meat substitutes are already fortified – for example, 24% of plant-based meat substitutes in Australia are fortified with vitamin B12, 20% with iron, and 18% with zinc (5). These nutrients could also be supplied by other food groups within our diet, such as seafood, dairy, and eggs (3).
Find out more – read the original articles:
Dussiot A, Fouillet H, Perraud E, et al. Nutritional issues and dietary levers during gradual meat reduction – A sequential diet optimization study to achieve progressively healthier diets. Clin Nutr. 2022 Dec;41(12):2597-2606. doi: 10.1016/j.clnu.2022.09.017. Epub 2022 Oct 4. PMID: 36306564
Salomé M, Mariotti F, Nicaud M-C, et al. The potential effects of meat substitution on diet quality could be high if meat substitutes are optimized for nutritional composition – a modeling study in French adults (INCA3). Eur J Nutr. 2022 Jun;61(4):1991-2002. doi: 10.1007/s00394-021-02781-z. Epub 2022 Jan 31. PMID: 35098325
External references:
Van Mierlo K, Rohmer S, Gerdessen JC. A model for composing meat replacers: Reducing the environmental impact of our food consumption pattern while retaining its nutritional value. J Clean Prod. 2017;165:930-950. doi: 10.1016/j.jclepro.2017.07.098
Mertens E, Biesbroek S, Dofková M, et al. Potential Impact of Meat Replacers on Nutrient Quality and Greenhouse Gas Emissions of Diets in Four European Countries. Sustainability. 2020;12:6838. doi: 10.3390/su12176838
Curtain F, Grafenauer S. Plant-Based Meat Substitutes in the Flexitarian Age: An Audit of Products on Supermarket Shelves. Nutrients. 2019 Oct 30;11(11):2603. doi: 10.3390/nu11112603.
