Because metabolic insulinemia is out of control these days and I find the keto people's studies quite convincing (look into Ivor Cummins' presentations on YouTube), in addition to hearing similar points of view even in some anti-keto diets. It seems pretty likely to me that sugar is very easy for us to over-consume in modern lifestyles.

Less convincing to me is the full-on keto diet itself. It's great that it exists as it started an excellent conversation on diet, but I rule it out because most cultures' dietary staples have been starchy carbs.

The problem imho is:

- It's too easy to overconsume carbs in modern lifestyles, and some of the carbs we consume spike our insulin too much (certain GMO crops in particular).

- It's too easy to consume non-whole-food carbs. Whole foods come with things that reduce the metabolic burden of eating them (fiber, antinutrients like phytates, antioxidants).

- The people who subsisted on carb-based staple foods led significantly more active lifestyles in the past than most people today, and did not have the abundance of food that we do now.