Prof. David Tilman : 4. Solving Problems of Diet, Health, and Environment at the Same Time

4. Solving Problems of Diet, Health, and Environment at the Same Time

Diet-Health-Environment Trilemma

Agriculture has a great impact on the environment, but what has an impact on agriculture?
Professor Tilman came to a conclusion that it is our diet. Changing our diet would change the crops we grow and the livestock we raise. Some types of food are better for the environment than others. If we eat more of these foods, then more of these foods will be cultivated.

In addition, diet also affects health, which is extremely important for us.
Diet has an impact on the environment through agriculture and on our health. In other words, food, health, and the environment are tightly linked with one another. Professor Tilman called this a "trilemma." He believes that changing our dietary choices will help solve this problem.

Diets that are Good for People and the Environment

How can we change our dietary choices? We need the motivation to change. We need to find food that people enjoy and that is both good for our health and good for the environment.
Together with scientists in other fields, Professor Tilman gathered a huge amount of data and introduced some diets that are both better for our health and the environment. One of those healthy diets is a Mediterranean diet, which is high in whole grains such as whole-wheat flour, vegetables, legumes, nuts, healthy oils such as olive oil, fruit and fish, and is low in red meat (meat from mammals such as cattle, pigs, sheep, horses, and goats).

Professor Tilman also suggested a traditional Japanese diet, which consists mainly of vegetables and fish, and also some traditional vegetarian diets in India, both of which are very tasty, good for health and the environment.

Professor Tilman analyzed 15 types of food from the aspects of both environmental risks and health-related risks. He found that red meat and processed red meat (bacon and ham) were harmful to health and the environment while grains, legumes, vegetables, nuts, and fruit were good for both health and the environment. This proved that the food that is healthy for us is also good for the environment.

The graph above shows the association between a food group's impact on mortality and its environmental impact.

The graph above shows the association between a food group's impact on mortality and its environmental impact. A larger value on the vertical scale (upper) means a higher impact on the environment, and a larger value on the horizontal scale (to the right) means a higher impact on health.

Why is red meat harmful for the environment? Cattle require lots of feed to grow to maturity and they release methane, a potent greenhouse gas. Therefore, producing meat places a significant environmental load on the planet.
Professor Tilman does not think that we should stop eating red meat. Red meat contains important nutrition that children need to grow strong and healthy. But many people in richer countries eat three times as much red meat as they need, which is neither good for their health nor the environment. According to Professor Tilman's analysis, greatly reducing the amount of red meat that we eat would be highly beneficial for both our health and the environment.
The research on diet, health, and the environment conducted by Professor Tilman has been adopted in national policies and in the field of health science.

Major Problems related to Our Future

Professor Tilman thinks that because we have become the dominant species on Earth, we should be more aware that our behavior greatly influences the future of the planet, and pay more attention to how we meet our needs for food and energy.

His mother and children

Both are huge problems; however, Professor Tilman wants young people to know that we can solve these problems while still living a fulfilled life. Changing our diet is not difficult, and this can be achieved while enjoying food. First of all, you can change one food type at a time every day by trying new foods that are tasty, better for health and the environment.

With his wife, Cathie, in Santa Barbara, CA

You can also invite your friends to your home for a delicious, healthy and sustainable dinner, or invite them to prepare it with you next time. Taking a train instead of a car would be the first step in solving energy problems.

With his first grandchild

Professor Tilman believes that many small steps taken by each of us will make our lives better and our planet sustainable.

Editor-in-chief: Itaru Yasui, Former Vice-Rector, United Nations University / Professor Emeritus, The University of Tokyo
Address from the Editor-in-Chief
Editorial supervisor: Shizuka Hashimoto, Associate Professor, Graduate School of Agricultural and Life Sciences, The University of Tokyo; (Affiliation is at that time of release.)