If I have an unclogged bathtub (normal metabolism) - I can fill the tub quickly with water (a carbed up meal) with water and then it drains out.
The problem is when you combine high fat with low fiber carbs (donuts, meat AND potatoes, cake, peanut butter) - you clog the tub and dump water into the tub.
Low carb diets are associated with higher all cause mortality - and are not sustainable for the planet.
There's hundreds of thousands of people currently having success with no-shellfish diets to manage their shellfish allergy; yet these people don't go around using words like "reversed" or "cured" in reference to their allergy, the way keto people do with insulin resistance. And most of those keto people having apparent success would fail an OGTT (a test that actually measures insulin sensitivity, unlike fasting BG/insulin or HbA1c) if they took one.