Moderately reduce meat consumption and eat more fruit, vegetables and whole grains, as recommended by the German Nutrition Society? To follow in the footsteps of our southern neighbors and eat fish and seafood more often? Or even switch completely to a vegan diet? A new study from the University of Bonn shows that the answer to these questions is not as clear-cut as one might think — depending on which effects one looks at in detail. The findings appeared in the journal Science of The Total Environment.
950 kilograms of food and drink are consumed by every citizen in the EU every year — a small mountain, as heavy as a small car. Globally, food accounts for a quarter of human greenhouse gas emissions. A large proportion of this is due to livestock farming: animals convert only a small proportion of the calories they are fed into meat. Ruminants also produce methane, which further accelerates global warming.
What we eat also has consequences for our health and animal welfare. If we want to compare diets, we should also look at these aspects. Experts also refer to the optimal health of humans, animals and the environment as the “One Health” perspective. “However, studies that apply this perspective to nutritional issues are still rare,” explains Juliana Paris of the Center for Development Research (ZEF) at the University of Bonn.
Current diet compared with three alternatives
Paris, together with colleagues, has conducted an analysis that aims to fill this research gap to some extent. “To do this, we took a look at examples of what products are on the menu of people in North Rhine-Westphalia,” she explains. “We then compared this reference diet with three different scenarios: a change according to the recommendations of the German Nutrition Society (DGE), a change to a Mediterranean diet with more fish and seafood, and a change to a vegan diet.”
In each of these three scenarios, the foods were chosen to differ as little as possible from the reference diet. “This means, for example, that in the Mediterranean variant, we increased the amount of fish and seafood, vegetables and grain products,” Paris says. In addition, the overall product selection was to contain the same nutrients in similar amounts as before. The researchers thus obtained a “food basket” for each scenario, which they then analyzed further.
“To do this, we relied on various databases,” says Dr. Neus Escobar of the Institute for Applied Systems Analysis in Austria, who supervised the work. “With their help, we were able to estimate, for example, the effect of each diet on certain environmental aspects — such as the amount of climate gases produced during its production or the water consumption. We took a similar approach to assessing the effect of each diet on health.” Red meat, for example, is known to increase the risk of certain cancers and cardiovascular disease.
The researchers estimated the consequences for animal welfare using several indicators. These included how many animals lose their lives as a result of consuming the food and the conditions under which they are kept. “But we also used the number of neurons or the size of the brain in relation to the body to estimate the extent to which the respective animals actually suffer as a result of their use,” explains Juliana Paris.
Fish instead of steak helps the environment but harms animal welfare
Each of the three diets would be sustainably beneficial from a One Health perspective. But not under each aspect: Thus the vegan nutrition scored best in many areas. However, the production of vegan food involves increased water consumption. “In addition, vegans have to take certain nutrients separately, such as vitamin B12, vitamin D and even calcium,” says Paris.
The Mediterranean diet (although healthy) also results in increased water requirements due to the high proportion of nuts and vegetables. Moreover, if — as assumed in the study — the meat consumed is completely replaced by fish, its effects on animal welfare are surprisingly negative: since fish and seafood are significantly smaller than cows or pigs, for example, considerably more animals suffer under this type of diet. Moreover, the increased consumption of honey, which requires intensive management of bee colonies, also has a negative impact.
“It would therefore be advantageous to cover less of the protein requirement overall from animal sources. In addition, many people today eat diets that are far too rich. If they reduced the amount they ate to what they really needed, that might have additional positive effects.”
- Neus Escobar
According to the study, the DGE recommendations are indeed heading in the right direction. However, in terms of human health, the other two options are better. Nevertheless, the data show here, too: If you give up meat more often and instead load whole grains, vegetables and fruit onto your plate, you’re not only doing something good for yourself, but also for animals and the environment.
