Sagging skin/cellulite/stretch marks without surgery

H., as always, has lots of good advice above.

I'd add - and this is just my opinion - that a very large fraction of people who lose substantial weight in actuality have less of a problem with loose skin than people just starting on weight loss (or part way through weight loss) seem to fear that they will have themselves.

I'd suggest reading posts in the "Success Stories" forum about people who've lost substantial weight. Many of them are honest about loose skin, including showing pictures in swimsuits or the like. I think you will be pleasantly surprised, in many cases, by how moderate the issue really is.

It's true that some people decide to have surgery, but from reading posts here it seems to me that it's a minority. Skin does shrink, but it can take some time after weight loss. For one thing, until most fat is gone, the remaining fat tends to conspire with gravity to keep skin stretched out. My loose skin (after losing about 50 pounds at age 59-60) kept shrinking at least well into my 2nd year of maintenance, and perhaps slowly beyond that. I had been obese for around 3 decades before that weight loss. Now, heading into year 4 of maintenance, I don't think I'm significantly saggier than other women my age who have always been at a healthy weight. Certainly, people who newly meet me are often visibly surprised if I say I was recently obese, even if they're meeting me when I'm dressed in close-fitting clothing, swimsuit, sleeveless tops, etc.

There's almost certainly a genetic component, but I agree with H. that a healthfully moderate weight loss rate, good nutrition, exercise, adequate hydration, etc., are your best bets. Skin is an organ. The things that keep other organs healthy also keep skin healthy and as willing as it can be to be elastic and recover.