Hi thanks for asking question. Usually foul smell because of bloating or constipation related bowel problem... So avoid fas forming food like cabbage , cauliflower etc. Avoid fatty food. Drink more water. Early in the morning take lemon water in which will relieve you from indigestion. Take banana .. Oats are reach in fiber , thiamin , vitamin E .so cooked oatmeal good in soothing stomach. Fiber supplement can be taken. Mostly these will benefit but... If still problem continue celiac disease like malabsorption syndrome or colitis or infkamatory bowel disease like condition searched for ...by colonoscopy and biopsy.. Take care. Dr.Parth .