If by "keto" we're talking about "ketogenic diet" that's means the body has fundamentally changed its metabolism away from using glucose and instead uses ketone

If by "keto" we're talking about "ketogenic diet" that's means the body has fundamentally changed its metabolism away from using glucose and instead uses ketones for energy. That's what ketosis actually is. Getting to this state and maintaining it is far harder than, say, paleo or mere "low carb". I don't have anything against any diet, just saying that ketosis isn't necessarily an easy alternative, it is an extreme practice. Most folks can do just fine with a bit of moderation in eating and regular exercise over the long-term (by long-term, I mean forever).