Any tips for over 50's stomach flab and sagging skin?

Hey all, and anyone out there who can relate and maybe offer some quality suggestions to help out, I am super fit at 56, but am still finding flab on my gut and sagging skin on my arms; which I am guessing is due to being post menopause.

I see so many adds and women showing up with flat stomachs and toned arms, but I don't understand if they are fake or have had surgery to help.

Is there really any way to reboot the metabolism and burn off that fat and tone up?