Saggy skin has a LOT to do with your genes. If your mom was heavy or even has saggy skin from having babies then you most likely will too. And if you do have certain skin with low elasticity, then there’s not much you can do to prevent it… However it will adapt and shrink to a point.. but that is all… You can’t do any certain exercise to lose the extra skin but you can build your muscles under the skin to fill out your skin more.
I am not an expert in any way but I’ve spent a lot of time reading about this topic. Preventing sagging skin has a few things that you have to take into account. One factor is age which I don’t think needs a lot of explaining. Another factor is the amount of weight you are losing and time. The quicker you lose weight the more prone you are to get sagging skin, your skin is an organ and it takes time for it to adapt to the new body. Another factor is nutrition, the skin is a complicated organ that needs various nutrients in order to have elasticity, and another factor is hydration. So as long as you are eating a well balanced diet which is nutritious and you’re not just counting calories and eating empty foods, stay hydrated and do some weight training to. Encourage muscle development,. Even if you do get some sagging. Skin, it will go away.