Which diet is better: low meat, Mediterranean or vegan? This was investigated by the Rheinische Friedrich-Wilhelms-Universität Bonn. Animal welfare and environmental impacts also played a role.
Which is better: reducing meat consumption and eating more fruit, vegetables and whole grain products, as advised by the German Nutrition Society (DGE)? Do the same as our neighbors to the south and eat fish and shellfish more often? Or be completely vegan?
A new study from the University of Bonn shows that the answer to these questions is not so clear when aspects of animal welfare and environmental impact are also included. The results are published in the journal Science of The Total Environment.
Diet responsible for a quarter of greenhouse gases
Globally, food is responsible for a quarter of human greenhouse gas emissions. Much of this is due to farming: animals only convert a small portion of the calories they eat into meat. Ruminants also produce methane, further accelerating global warming.
If you want to compare forms of nutrition with each other, you have to take into account the optimal health of humans, animals and the environment at the same time. Experts refer to this as the “One Health” perspective.
The best diet: low meat, Mediterranean, vegan?
Juliana Paris of the Center for Developmental Research and her team compared three diets. “We look at the products that people in North Rhine-Westphalia eat,” she explains in a press release. “We compared this reference diet with three scenarios: a switch according to the DGE recommendations, a switch to a Mediterranean diet with more fish and shellfish, and a switch to a vegan diet.”
In each of these three scenarios, foods were chosen to differ as little as possible from the reference diet. In addition, the selection of products must contain the same nutrients in similar amounts as above. The researchers received a “food basket” for each scenario.
To what extent do cattle suffer due to their breeding?
With the help of databases, the effect of each diet on environmental aspects, such as the amount of greenhouse gases produced during its production or water consumption, could be estimated. That explains Dr. Neus Escobar of the Austrian Institute for Applied Systems Analysis. “We used a similar approach to assess the impact of each diet on health.” Red meat is known to increase the risk of certain types of cancer and cardiovascular disease.
The researchers estimated the consequences for animal welfare using a series of indicators: how many animals lose their lives as a result of consuming food and in what conditions they are kept. “We used the number of neurons or the size of the brain in relation to the body to estimate to what extent the respective animals actually suffered from their use,” explains Juliana Paris.
The vegan diet worked better
Result: The vegan diet performed better in many areas. However, vegan food production is associated with higher water consumption. “In addition, vegans must provide certain nutrients separately, such as vitamin B12, vitamin D or calcium,” says Paris.
The Mediterranean diet, although healthy, also has a higher water requirement due to the high proportion of nuts and vegetables. If the meat consumed is completely replaced by fish, its effects on animal welfare are also negative: since fish and shellfish are significantly smaller than cows or pigs, many more animals suffer from this form of nutrition. The increased consumption of honey, which requires intensive management of bee colonies, also has a negative effect.
The diet is too rich.
“It would be advantageous to cover less of the protein requirement of animal origin in general”, emphasizes Neus Escobar. “In addition, many people today eat too much food. If they reduced the amount of food they eat to what they really need, that could have additional positive effects.”