I've been on it a year. Went hard the first six months, but have been exercising less and cheating more since about June. I lost forty pounds overall, though the majority of it was in the first half of the year. Even with the lack of exercise and cheating, though, i've managed to keep the weight I did lose off just by being smart about carb-intake. I did recently get addicted to peanut butter, though, which is low-carb, but still has a ton of bad ingredients in it that can fuck with your system. Going to try going hard again and lose more weight.
Personally, I love it. I do miss things like brownies and pizza, but keto pizza is pretty good too- organic low carb tomato sauce mixed with mozerella cheese and cooked pepperoni slices. I could make a bowl of that shit with a ton of fat in it and less than 5 net carbs. I ate that shit three times a week and bacon and eggs every morning for six months and lost forty fucking pounds. It's incredible how much you can benefit just cutting carbs and sugar out of your diet. Cooked everything in olive oil, bacon grease, and butter too. I was going through 1/3 to 1/2 a stick of butter PER DAY at one point, losing weight.
Fuck I need to stop cheating with the fruit and rice and get back to the fat game. I also lowered my fat intake and increased my protein intake in the last six months, which can fuck with insulin levels and knock you out of ketosis. Fuck the turkey bacon, yo, I'm back to the real shit.
By the way, I encourage all of you to stop buying packaged bacon and buy it directly from a butcher or meat counter instead, if you can. It's typically the same price, and in many cases cheaper, and it's SO much better. You know how that packaged shit shrivels up when you throw it on the frying pan? Not butcher/meat counter bacon. The stuff I get from the Albertson's meat counter stays thick and juicy, and cooks so, SO nicely.
Also, anyone trying to eat healthier: buy a bag of power greens (spinach, kale, chard, and mustard greens are the best), and eat a bowl of it with one or two meals every day. It's very low calorie, very low carb, and packed full of good shit. If you eat a couple leaves with every bite or two of your meal, you don't even notice the taste, it'll help you feel more satisfied after eating, and it's so, so good for you.
So yeah, count me in the group that's had a profoundly positive impact from a ketogenic, high fat, low carb diet. In addition to weight loss, my stamina has increased, my sleep has gotten significantly better, and I no longer feel sluggish and tired in the middle of the day. My birthday was last weekend and my girlfriend took me to a Cuban restaurant, where I ate a pile of rice (it was my birthday, so I decided to cheat), and about half an hour later needed to sit down because of the amount of carbs I took in making me feel tired. My girlfriend eats tons of bread and loves fruit juice (she's also in great shape), but when I occasionally convince her to go a day or two without the carbs, she admits how much more energetic she feels during the day. You can eat a full ketogenic meal and hit the gym or go for a run quickly after. Try doing that shit after a bowl of pasta.
Seriously, fuck carbs.