Zero.

As long as I'm not actually nuking my food in flimsy plastic containers, I'm fine.

I honestly think it may be an engineered distraction to the nightmare that is the current food system - processed trash carbohydrates, seed oils, and sugars. The majority of the population (in the US) overweight and obese.

"Focus on the microplastics", they say. No, I say "focus on whole foods". And, of course, I eat carnivore, which I'm convinced is by far the best for me.