Sorry to rain on your parade, but you will regain the lost weight as soon as you stop with the appetite suppression regimen. The only permanent weight loss solution is to revamp the feeding paradigm by examining the core motivation for excess food and toxic quasi-nutrients.
Sorry to rain on your parade, but this was in fall of 2020 and I have not regained the weight. I still eat mostly keto, probably closer to an average of 1600 kcal/d now (I don't count calories anymore), and don't use the appetite suppressants anymore either, except for when I have a ton of work, maybe once a month average. I initially regained 20 pounds in the 6 months following the diet thanks to some rebound junk food, but it came back off once I got back to eating healthy.
Keto naturally leads me to lots of largely unprocessed whole foods. Eggs, cheese, chicken, milk, some red meat, butter, etc - organic / cage free / free range / not treated with hormones, of course.
Most people who rapidly lose weight will gain it back. The keyword here is most. There are exceptions to pretty much everything. There's no reason to doubt this person is one. That doesn't make their strategy good advice.
Before the regimen where I lost 80 lbs in 3 months, I regularly ate fast food, pizza, etc. After the regimen (off appetite suppressants, no longer calorie counting, no longer doing intermittent fasting), I still am doing keto, meaning I avoid the junk I used to eat that got me to current+80 lbs.
I suspect this permanent change in diet is what has allowed me to keep the weight off, though the more extreme regimen was what allowed me to lose so much so fast.
What about my story? I’m 170lbs down using keto and IF and have kept it off going into my 5th year. Also was an insulin dependent Type 2 diabetic who was off insulin 3 months in and haven’t taken it since.