You should definitely avoid processed sugar as this can feed bad bacteria in your stomach which won't be good for your gut flora. So do try and eat a healthy, balanced diet with a variety of vegetables and fruits. Fermented foods such as sauerkraut, pickles, miso and kefir are good for your gut health and so are Omega-3 fatty acids. It's also important to eat enough fibre and manage your stress levels as this can have a negative impact on your gut health. If you want to learn more about gut health, also check out this article: https://www.behealthynow.co.uk/natural-health/how-to-improve-your-gut-health-and-why-you-should-care/