Cheese is one of the most keto-friendly foods due to its high fat, protein, and low carbohydrate content. Aged hard cheeses like Parmesan, Gruyère, Gouda, Pecorino Romano, and aged cheddar are especially ideal because fermentation lowers lactose while concentrating nutrients, healthy fats, and flavor. Comfort Keto recipes frequently use these cheeses to add richness, protein, and depth without significantly increasing carb intake.