Which diet is better: moderately reduce meat consumption and eat more fruits, vegetables and whole grain products as recommended by the German Nutrition Society? Follow the example of Germany’s southern neighbors and eat more fish and seafood? Or even switch completely to a vegetarian diet? A new study from the University of Bonn (Germany) shows that the answers to these questions are not as clear-cut as one might think — depending on which effects one looks at closely. The results are published in the journal Science of Total Environment.
Each EU citizen consumes 950 kilograms of food and drink annually — a large amount, the weight of a small car. Globally, food accounts for a quarter of human greenhouse gas emissions. A large part of this is due to livestock farming: animals convert a small portion of the calories they eat into meat. Ruminants also produce methane, which further accelerates global warming.
Furthermore, what we eat also has implications for our health and animal welfare. While comparing diets, these aspects should also be taken into consideration. Experts refer to the optimal health of people, animals, and the environment as the “one health” perspective. “Studies that apply this perspective to nutritional issues are still rare, though,” explains Juliana Paris of the Center for Development Research (ZEF) at the University of Bonn (Germany).
Actual food basket compared with three alternatives
Paris, along with colleagues, conducted an analysis that aims to fill this research gap to some extent. “To do this, we looked at examples of what products people in North Rhine-Westphalia have in their food baskets,” he explains. “We then compared this reference diet with three different scenarios: a change according to the recommendations of the German Nutrition Society (DGE), a shift to a Mediterranean diet with more fish and seafood, and a shift to a vegetarian diet.”
In these three scenarios, the foods were chosen to differ as little as possible from the reference diet. “This means, for example, in the Mediterranean version, we have increased the proportion of fish and seafood, vegetables and grain products,” says Paris. In addition, the overall product selection should contain the same amount of nutrients as before. This gave the researchers a food basket for each scene, which they further analyzed.
“To do this, we relied on different databases,” said Dr. Neuss Escobar of the Institute for Applied Systems Analysis in Austria, who supervised the work. “They enabled us, for example, to estimate the impact of each food on certain environmental aspects — such as the amount of greenhouse gases produced during their production or water consumption. We took the same approach to assess the impact of each food on health.” Red meat, for example, is known to increase the risk of certain cancers and cardiovascular disease.
Researchers have estimated animal welfare outcomes using various indicators. This includes how many animals die as a result of food consumption and the conditions in which they are kept. “But we used the number of neurons or the size of the brain relative to the body to estimate how much the respective animals actually suffer when they are used,” explains Juliana Paris.
Fish instead of steak: good for the environment, bad for animal welfare
Any of the three diets will have lasting health benefits. However, this is also at the expense of other aspects. Vegan diets scored best in many areas. However, water consumption increases with the production of vegetarian food. “In addition, vegetarians need to consume certain nutrients differently, such as vitamin B12, vitamin D and even calcium,” Paris says.
The Mediterranean diet (although healthy) increases water requirements due to the high amount of nuts and vegetables. Furthermore, if – as the study assumes – the meat consumed is completely replaced by fish, the impact on animal welfare is surprisingly negative: as fish and seafood are much smaller, for example, cows or pigs, considerably more animals suffer as a result of this diet. Increased consumption of honey, which requires intensive management of bee colonies, also has negative effects. “Therefore it is beneficial to meet less of your overall protein needs from animal sources,” emphasizes Nues Escobar. “Also, many people these days have diets that are significantly too rich. If they reduce the amount of food, which they really need, that can have an additional positive effect.”
According to the survey, the DGE recommendations are on the right track. However, in terms of human health, the other two options are better. Still, here’s the facts: If you skip meat more often and instead put whole grains, vegetables, and fruits on your plate, you’re not only doing something good for yourself, but also for animals and the environment.