Why Does One Experience Constant Hunger?

Hi, I have Gastritis and I m on medication for it. It has helped with the pains. However, I m experiencing constant hunger and cravings I eat a healthy diet, I make sure that I eat low Gl foods, stay hydrated, avoid caffeine and alcohol too. I am active. My energy has dropped so I walk each day as this is all I can handle presently. I m very concerned as I cannot stop eating and feel hungry and weak in between. This was a problem before getting Gastritis. I have spoken to nutritionists and done much research but can t seem to find a remedy. I would really appreciate your help. Kind Regards, Kathleen