And before I get someone saying "just run at an 'energy deficit' - consume less calories than you burn" - I say, if you want to look and FEEL good, the person who eats 1,500 calories a day of carbohydrates vs 1,500 calories a day of protein, vegetables (carbohydrates largely bound by fiber), etc - will look and feel vastly different. This is why it's not just as simple as calories in - calories out.
Most people seriously interested in this topic should already be familiar with the "insulin index" paper (was reposted to HN within the last couple weeks).
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.
Anything else is hogwash, because calories are not calories.