> All the CO2 they exhale got the carbon from plants, which recently pulled it from the air. Humans are carbon neutral. This would be true AFAICT if we somehow

> All the CO2 they exhale got the carbon from plants, which recently pulled it from the air. Humans are carbon neutral. This would be true AFAICT if we somehow managed to eat without any CO2 emissions. But agriculture is a huge driver of CO2 emissions and so are logistics, electricity for cooking etc.. So while the CO2 we exhale comes from the atmosphere through plants, animals and so on, we inevitably cause a lot of CO2 emissions as a side-effect in the process.