Ann is an ectomorph. Her build is an anatomical type..has nothing to do with diet. She probably could not gain weight if she tried...besides which, some say, “the closer to the bone, the sweeter the meat.”
I was/am an ectomorph, too. Around the time I turned 50, my basal thermostat decided to reset. Nowadays, I can gain weight if I eat lots of sweets, but otherwise my new set point seems stable. And it is, sadly, NOT ectomorph. LOL
Before then, I couldn’t gain weight no matter what I did.
Ann’s about at the age where she could experience the same.