Understanding human perception and requirements on nutrition for cancer prevention and condition management is important so that nutrition applications can be catered for cancer patients. In this paper, web-scraping was conducted to understand the public’s perception, attitude and requirements related to a plant-based diet as a recommended diet for cancer prevention and condition management. Text and sentiment analysis were carried out on results gathered from 73 social sites to determine whether non-cancer and cancer patients use plant-based diets, how they have been consumed, their benefits in the prevention and condition management of cancers, the existing myths/fake news about cancer and what do cancer patients need in a nutrition app. Results of the text analysis highlight missing gaps in existing apps to include a lack of credibility and endorsement by professionals. Future nutrition apps should provide personalized diet, symptoms management, good user experience, credibility, and emotional and mental health support.