Talk to Gastroenterologist on IBS- Weight Gain

Hi, I was diagnosed with IBS about 4-5 years back and have gone to various doctors done different medications and have also developed acidity problems, but currently I am not taking any medicines and controlling my condition through controlled diet and routine. But my real problem is I lost around 16 KGs 2 years back and since than I am unable to gain weight, currently my weight ranges from 50-53 Kgs. I had an active routine, use to do gym 5 days a week, but I am unable to do so due to restricted diet problem. Recently I have heard Amino Plasma test for IBS, can I know more details about it and how can it help an IBS patient.