Â鶹ÒùÔº

255 grams per week. That's the short answer to how much meat you can eat without harming the planet. And that only applies to poultry and pork.

Beef cannot be eaten in meaningful quantities without exceeding planetary boundaries, according to an article by a group of DTU researchers in the journal Nature Food. So says Caroline H. Gebara, postdoc at DTU Sustain and lead author of the study.

"Our calculations show that even moderate amounts of red meat in one's diet are incompatible with what the planet can regenerate of resources based on the environmental factors we looked at in the study. However, there are many other diets—including ones with meat—that are both healthy and sustainable," she says.

How much is 'less'?

The researchers' first goal was to investigate whether it is even possible to fulfill the nutritional needs of the entire global population without exceeding planetary boundaries. According to the calculations, it is possible. But it will require a change in our food consumption on both a global and individual level, says Caroline H. Gebara.

"The global shift requires political action at the top level, while the individual shift will be much easier if we have better guidance and frameworks that support sustainable choices," she says.

The next goal of the research was therefore to come up with concrete figures for how much of different foods you can eat without consuming more of the earth's resources than it can regenerate, says Caroline H. Gebara.

"Most people now realize that we should eat less meat for both environmental and health reasons. But it's hard to relate to how much 'less' is and whether it really makes a difference in the big picture. Therefore, based on the planetary boundaries, we have calculated a concrete figure—255 grams of poultry or pork per week—which you can actually visualize and consider when you are standing in the supermarket," she says.

In Danish supermarkets, a pack of two chicken breast filets typically weighs 280 grams which is slightly over the limit of what one person can eat in a week without exceeding the planetary boundaries.

Not either-or

The research team's calculations take into account a number of environmental factors such as CO₂ emissions, the consumption of water and land use, as well as the health impact of a particular diet. In total, they have examined more than 100,000 variations of 11 types of diets and calculated their respective environmental and health effects.

And the calculations clearly show that a diet with even moderate amounts of red meat—beef or lamb, for example—exceeds planetary limits.

A pescetarian, vegetarian or vegan diet, on the other hand, is likely to stay within the limits of what the planet can support. But this also depends largely on the specific products included in the diets.

In addition, different combinations of diets, such as vegetarian but with dairy or eggs, can also be sustainable.

And that's exactly what Caroline H. Gebara hopes that the study will help more people realize: That a sustainable diet can take many different forms.

"For example, our calculations show that it's possible to eat cheese if that is important to you, while at the same time having a healthy and climate-friendly diet. The same is true for eggs, fish and white meat, but the premise is of course that the rest of your diet is then relatively healthy and sustainable. But it doesn't have to be either-or."