https://www.youtube.com/watch?v=U1f9g9Y1wm0
They both lost some weight, although the brother who was on the low-carb diet ended up virtually pre-diabetic.
It's been known for decades (outside of the HN reality distortion field) that excess accumulation of intramyocellular lipids in skeletal muscle is the primary underlying mechanism driving Type 2 Diabetes, so that's pretty much the outcome you'd expect.
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.
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.
[1]"Prediabetes happens when your blood glucose levels are higher than normal, but not high enough to be diagnosed as diabetes. Prediabetes usually occurs in people who already have some insulin resistance."
So, it doesn't sound right that he would be pre-diabetic when his blood glucose levels would be low. Seems that doctor made the assumption that because his blood insulin was low, his body would just stop producing it at some point, and that's not how it works.
[1]https://my.clevelandclinic.org/health/diseases/22206-insulin...
"Low-carb" dude removed all fruits and vegetables. He didn't do low-carb, he did no-carb - in his own words: "meat cheese eggs".
The whole clip just reeks of b.s. though, neither of these guys would be getting air time if the results weren't click-bait controversy fodder. The b.s. incentives are clear.