I'm doing keto and its working well, but its not a miracle diet or anything. Eating lots of fat keeps you full for a long time. I used to be hungry an hour after eating ~300g of pasta, now when I eat a fatty breakfast i'm not even slightly hungry until 7/8pm at night. The fullness aspect is why people lose weight easily on keto, its quite difficult to overeat when not involving carbs. Keto is a low carb/moderate protein/high fat diet. Note the moderate protein, most of the calories are meant to come from fat, you aim to eat enough protein to prevent muscle degeneration but not much more.
As for actual weight loss, in the first week or two you dump a lot of water weight, around 10lbs/4.5kg usually because carbohydrates cause your body to retain extra water. After you've dumped the water weight the amount you lose depends entirely on the calorific deficit you are using. On average I'm dropping 2lbs a week, which is normal in any proper diet.