Can IBS or hiatus hernia cause weight loss? If I do gain weight, only my cheeks get bigger, body stays skinny *not genetic. Any tips to gain weight?

See your doctor. It is rare to need to gain weight. You may be low normal. To gain muscle instead of fat increase your exercise and protein intake. Work with your doctor and a physical trainer. Your doctor will check you for thyroid issues as well as other abnormalties if you are losing weight with no reason.Often ibs and constipation are emotional problems and you may be focusing on the wrong problem.
The issues of. Ganing weight are most due to food consumptionand weight bearing excercise. Start a weight lifiting regimen and eat protein. A samll iatal hernia, if asymptomatic, should not do it. The ibs may be better controlled with anxiety control so talk to your doc about this. Good luck.