If you are experiencing discomfort and soft stools after eating junk food, there are a few steps you can take. First, try sticking to a light diet with foods like soup, broth, soda crackers, and toast. Avoid heavy or overly sweet foods like large amounts of red meat or undiluted fruit juices. If the symptoms persist or worsen and affect your quality of life, it may be a good idea to consult a doctor for further evaluation and advice.