My children were pretty young when I had weight-loss surgery and we still told them. They needed to understand why I couldn’t pick them up and hold them for a while since you aren’t supposed to lift much weight until a week or so has passed. My kids needed to know why they couldn’t just run in and dive on me for hugs. One stray knee in my tummy era would’ve been incredibly painful and could cause an injury. I didn’t want them to feel rejected, so I really wanted to explain things and to let them know that it would all go back to normal eventually.
My husband and I kept the focus off my weight though, just in case little ears might hear the words and question whether their own bodies were thin enough. We emphasized that I was having this surgery so I could be more active with them and so I’d be around for a long, long, time since it would help me become healthier.