There are people who eat literally the same meals every day, for years, and the opposite would stress them for a number of reasons. There was a recent article about it linked in HN too, I think ?
Some guess it has to do with immune system activation, GI biome optimized for digestion of these repetitive specific foods you eat, etc.
I often wonder if benefits of keto actually come not only from ketones themselves, but also from the fact that keto diets are often very limited, and often to often (relatively) hypoallergenic foods.