We know that a climate friendly diet is plant based, with the potential addition of climate friendly animal products i.e. egg, fish, and poultry meat. Sometimes there is a concern that a climate friendly diet may constitute a problem from a health and nutrition perspective.
If we start with nutrition. It is easy to construct a climate friendly diet that consists of all relevant vitamins and minerals. But is it really how people eat? To understand that researchers let 1500 random Swedish people write down everything they ate for four days. The result showed that those with the lowest emission caused around 1,5 ton CO2-eq per person and food consumption, compared to around 2 ton in the highest group. But there were no relevant differences in nutritional intake. This means that both in theory and in practice there is no trade-off between eating environmentally friendly and nutritious.
Concerning health, it is a bit trickier as diseases typically evolve over decades and we have not followed people with specifically climate friendly diets for so long. Although, researchers do know that a high intake of red meat, which also causes large emissions, is associated with certain types of cancer. A high intake of vegetables, on the other hand, prevents certain types of cancer and that high intake of vegetables prevents certain types of cancer. By using these relationships researchers can estimate how many lives can be saved by adopting different kinds of diets. A study in the UK found that if people would eat a diet with 17 % lower emissions, the average life expectancy would increase by 8 months. Further, in a global study, the researchers found that a diet with somewhat lower emissions would save 5 million lives. If all human populations would adopt a vegan diet, the emissions would decrease even more, and up to 8 million lives would be saved.
We can thus conclude that eating more climate friendly means that we still get an adequate amount of vitamins and minerals. But more importantly, it would mean a lower prevalence of certain diseases that would actually save lives.