The downvotes are probably because of the "I wish I was fat so I could fast and walk". Both fasting and physical exercise are activities that are not fun when you have to do them. No one wakes up in the morning and says "yay I'm glad I'm fat so I can not eat things and work out!" They stop eating and start working out for the sole purpose of not being fat anymore.
As it was worded, it's a huge slap in the face to anyone who is overweight. It sounds like the parent is glorifying being overweight. Being underweight must suck too, but it can't make you feel any better when a fat person says "I wish I was as skinny as you so I could eat everything and just focus on bulking up" when you're trying to force yourself to do those things, likely to the point of physical illness.
As it was worded, it's a huge slap in the face to anyone who is overweight. It sounds like the parent is glorifying being overweight. Being underweight must suck too, but it can't make you feel any better when a fat person says "I wish I was as skinny as you so I could eat everything and just focus on bulking up" when you're trying to force yourself to do those things, likely to the point of physical illness.