I’d suggest you watch some videos on YouTube if you want “proof”. Few people here share pics and that’s fine - if you don’t want to believe people’s experiences here, you don’t have to but that’s on you. “Zero loose skin” may be an exaggeration, but that’s because we all have natural fat to cushion the organs as well.
Dry fasting has done wonders on my body for tightening up skin - I’m skinny to begin with, so I don’t really have to deal with the loose skin issue, but I can testify that I noticed my skin tighten dramatically after a prolonged fast and it’s definitely felt. Most people don’t dry fast for a long enough time to tighten loose skin as dramatically as you probably would like, so you will have to go for a prolonged fast if you want more results. But “refusing” to have loose skin doesn’t mean it won’t happen; our bodies take time to adapt and that’s perfectly normal. Remember what really matters is losing the weight.