That’s the obvious answer, surely, and one I’m disposed to agree with. But given that we’ve introduced a lot of new chemistry to our bodies over the last century or so, I’m suggesting that it may not be the only answer. This is not to say new chemistry is necessarily bad, either. Food and water in the industrialized world are massively safer from microbial contamination than they ever have been. People generally stay healthier, longer than ever in history. Nonetheless, if we’re inadvertently poisoning ourselves, we can do even better if we stop.