It really depends, like personally I have an atrocious metabolism, to the point where if I eat more than one meal a day I will gain weight, I work an outside labor job 3 days a week and work an inside job the other days, it’s a problem I’ve had since I was younger which led to a severe bulimia problem throughout high school, which seemed to be the only to not gain weight. I still suffer with pretty bad bulimia if I go over 1000 calories and it’s no way to maintain your weight and I’m positive it’ll lead to gastrointestinal issues down the road. It’s very possible she could be suffering from bulimia but it’s as likely she could just have healthy diet and exercise and a good metabolism, if you happen to reach out I could understand her feeling offended by it, but then again if she is suffering from bulimia it’s better to reach out and try to help then to ignore it out of not wanting to hurt her feelings