A dietary pattern that is healthy for both Belgians and the planet

A dietary pattern that is healthy for both Belgians and the planet

Research for WWF Belgium into more sustainable, healthier eating habits

WWF launched the European Eat4Change project to make young Europeans aware of ways to develop and adopt a healthier and more sustainable diet. Our current food system has a substantial environmental impact. With Eat4Change, WWF wants to make food production more sustainable, combat biodiversity loss and tackle the climate crisis. As part of this European project, on behalf of WWF Belgium, we analysed which products fit in a sustainable healthy diet for a family of four. We did this using our software tool Optimeal. The results show that a sustainable and healthy diet is also a little cheaper than the average Belgian's current dietary pattern.

Food plays a big part in our daily lives. Every day, we make choices about what to eat. The current food system not only contributes to deforestation, biodiversity loss and land degradation, it also plays a major role in climate change. Research by the IPCC reveals that the global food system is responsible for 21 to 37% of greenhouse gas emissions worldwide (IPCC, 2019). In addition, unhealthy dietary patterns contribute to diseases such as diabetes, cardiovascular disease and cancer. So a change in our diet could significantly benefit the health of both humanity and the planet. This is also supported by well-known studies, such as the EAT-Lancet report (Willett et al., 2019).

WWF Belgium wants to provide insight into what such a sustainable healthy diet should be like for Belgians. We calculated this using our software tool Optimeal. The study examined three different target groups: adults (aged 18-64), adolescents (aged 10-17) and children (aged 3-9). The results were subsequently combined to create an optimised diet for a family of four, comprising two adults, an adolescent and a child.

Research questions

The study focused on the following research questions:

  • Can different food choices contribute to gains in terms of the three sustainability criteria (people, planet, profit)?
  • Is it possible to improve our food consumption in such a way that it meets the goals of the Paris Climate Agreement and contributes to the quality of our environment and nature, while also adhering to nutritional requirements and being affordable?
  • What proportion of products from more sustainable agricultural systems can be purchased within this new diet without making it more expensive?

Result: Flexitarian diet for Belgians

The study has shown that Belgians can change their diet in a way that it is compatible with international climate targets, meets all nutritional requirements, and is no more expensive than their current diet. The optimised diet is flexitarian, which means that it still contains animal products, such as meat, milk, eggs and fish, but in much smaller quantities. This is also consistent with the government’s guidelines for a healthy diet. For example, eating meat twice a week and dairy three times a week is still possible, and the consumption of eggs will even increase. The optimised diet recommends higher consumption of vegetables, fruits and legumes. The same applies for nuts and grain products, which have a favourable profile in terms of both sustainability and health. In addition, plant-based meat and dairy substitutes, such as tofu, tempeh, vegetarian burgers and soy drinks, feature more prominently in the diet. On the other hand, the consumption of products with a high saturated fat, sugar or salt content, such as biscuits, soft drinks and processed meat, will decrease.

The new dietary pattern would halve the CO2 footprint, from 16.73 CO2 eq/day to 7.95 CO2 eq/day for a family of four. The new diet does not only have the potential to keep global warming below 1.5 degrees, but also limits the expansion of agricultural land, and averts negative impacts on biodiversity. The sustainable and healthy diet contains fewer products of animal origin, and fewer alcoholic drinks, snacks and soft drinks. These products are often relatively expensive, meaning that overall, the new diet is even slightly cheaper than the current one. This leaves room to purchase certified products that stimulate environmental sustainability as well as social responsibility in the production chain.
Graph - Composition of current and optimized daily diets for a family of four

Figure 1. Composition of current and optimised dialy diet for a family of four

Graph - Climate change impact of current and optimized daily diets - Family of four

Figure 2. Climate change impact of current and optimized daily diets for a family of four

Optimeal: Calculating a sustainable diet

We conducted this study using Optimeal, a software tool to optimise dietary patterns taking into consideration both sustainability and health. The starting point for this is a reference diet, based in this case on the most recent Belgian National Food Consumption Survey. This reference diet represents the current dietary pattern in Belgium, divided into three age groups (adults, adolescents and children). To guide the optimisation process in Optimeal, constraints were set on individual nutrients (such as vitamins and minerals), on food groups (through food based dietary guidelines), and on greenhouse gas emissions (ensuring global warming stays below 1.5 degrees). These constraints are based on the Belgian nutritional recommendations, the Paris Climate Agreement and the IPCC report on “Global Warming of 1.5 °C”. The environmental impact of food products was calculated using the Life Cycle Assessment (LCA) method. The product prices are based on those of the three largest supermarkets in Belgium.
Using Optimeal, the impact on the environment, such as CO2 emissions, land use, biodiversity loss and water use, and health was calculated for the reference diet, meaning the current average Belgian diet for the three age groups. The result reflects the current Belgian diet in terms of sustainability and health. This diet was subsequently optimised based on current nutritional guidelines. In the next step, this diet was optimised based on the climate change target. The result is an optimised diet that is both healthy and sustainable.

More information about Optimeal

About Eat4Change

With the international project Eat4Change, WWF seeks to inform young Europeans about sustainable food and the impact of their individual choices. WWF hopes this will make young people the engine for change. The project aims to encourage people to adopt a healthier and more sustainable diet, to collaborate with food producers and traders to stimulate sustainable agricultural production, and to create a political climate that will aid this transition.


Read more about Eat4Change (in Dutch)


More information




If you have any questions about this study, or would you like to know more about healthy and sustainable food, please contact Caroline te Pas
by email: caroline@blonkconsultants.nl or telephone: +31 (0)182 579970.