Check the sources for ingredients and recipes that will lower your impact. Wheat, corn, beans, chickpeas, lentils, rice, soy, nuts are great sources of protein.

Shop wisely and don't waste food, reducing the amount of food you buy in the first place.

Not as good as a plant-based diet, but reducing your meat intake has an impact, especially the highest offending meats (beef, lamb, goat).

That out-of-season fruit on the supermarket? It was probably flown in from another country. Eat locally grown food as much as you can.