the only time in my life that I did not experience the yoyo symptom after weight loss was when I went on Dr Richard Schulze 's entire incurable program (email me if you need more info on the save your life incurable program by schulze) with a 30 day juice fast.
I lost 60 pounds and though that was 10 years ago I still only gained 30 of it back which never ever happened in my life. I always gained it back--plus more.
I noticed this tendency long before they termed it yoyo syndrome and that is why I quit dieting. I think the colon cleansing is what helped with that Yoyo as Dr Christoper said after several Colon Cleanses he went from 4 large meals a day to 2 and had less hunger and more energy. I believe this was because with the mucoid plague removed, the body was better able to absorb the nutrients and wasn't ravenously hunger all the time for starving for nutation that the plague was blocking.
Amazingly at hacres.com, some people lost hundreds of pounds (as Dave the raw food trucker did) with a mainly raw food diet and find that unlike most people losing that much weight, there skin is not loose. Dave said on one of his videos that he went to a skin surgeon who did not believe he lost all that weight as his skin was not that loose or saggy.
I also read there or somewhere that someone who was left with a lot of loose skin and no money for the surgery to remove it, went on the hallelujah diet (or any raw vegan diet would do the same I suspect) and within 2 years her skin tightened back up due to the skin which is an organ regenerating from the high nutrition.
I would also considering adding an astringent herb externally like witch hazel tincture/ointment as these help tighten the skin and consuming apples which I read once helped and doing daily skin brushing to help with detoxing the skin.