I started a ketogenic diet in February 2019 and moved quickly to "carnivore" or "ZC" (zero-carb) in March 2019. I quickly lost 30 pounds, dropping to my "ideal weight", and my 50+ years of "dieting" and being hungry seem to be over. I don't try to be "perfect" ZC, as my body seems to tolerate a few carbohydrates at this point, but I'm certainly still closer to ZC than keto. Update 2025: Yes, it is hard to maintain this diet. I gradually regained 20 of the 30 pounds I had lost, and this year I've recommitted to staying in ketosis almost all of the time. I feel better when I'm in ketosis, but I'm addicted to carbohydrates and to sugar in particular. It's especially hard to resist carbs when eating socially. I must stay less than 20 g/day to maintain ketosis, and one poor day knocks me out of ketosis for 2 or 3 days.
I've tested various food restrictions, each for a month at a time, and I've found that I can tolerate dairy (hard cheeses and butter and heavy whipping cream) without noticeable symptoms. I also occasionally eat nuts (not peanuts, but pecans, walnuts, almonds and macadamia nuts). I eat very few fruits and vegetables.
I believe in IF (Intermittent Fasting), and most days all my eating is within a 6 to 8 hour window. My overnight fast almost always is more than 16 hours.