We are ecosystems. Be the jungle.
Inside, we are ecosystems. We have more microbes inside of us than our own cells.
In ecosystems, diversity is strength. All niches are full of competitors and predators. An invader has no chance of dominating. More likely, it will be recognized and put in it's place, possibly the belly of a predator.
Our invaders are just like ecosystem invaders. The cockroach is to the ecosystem what e coli is to you.
If the cockroach invades the alley behind a fast food restaurant, it'll find lots of food in a toxic, hostile environment. It'll thrive, since competitors and predators haven't survived the poison campaign. Salted Earth.
We are creating that fast food alleyway inside ourselves when we eat that same fast food. The preservatives and other industrial ingredients are literally poisons and destruction to our internal landscape and diversity.
Be the jungle. Make your environment the jungle.