When my oldest son was four, we visited my mother. We stayed about six weeks and he turned five while we were there. He had an undiagnosed medical condition, so he was a skinny little kid. Actually, both my sons were skinny when they were little but my younger son has a different build and people didn't hassle him about it. My younger son later put on weight, but I once saw an old photo of him and was shocked at how prominent his collar bone was at a young age because no one ever hassled him about being a bag of bones. He had a bigger bone structure and wild curly hair making his head look huge and people missed the fact that he was actually quite skinny. He's extremely introverted and didn't tell me at the time that he was intentionally gaining weight. Years later, he mentioned it was intentional. He said he was tired of being cold all the time and at age nine or whatever decided to just eat extra until he stopped feeling cold all the time, so he's been on the chubby ...
Raising Future Adults
Adventures in Parenting and Homeschooling My Twice Exceptional Kids