Most existing food recording tools rely on text-based recording, which makes it difficult for users to continuously record and is an unintuitive approach to understanding food content. Photo based recording is advantageous because it provides image-based input assistance and a quick understanding of food intake. Thus, we have constructed a multimedia food recording platform called FoodLog that helps users record their food intakes via photos through personalized image recognition. The number of food records uploaded by general public users exceeds 10 million as of July 2019. We discuss the technical framework and present various analyses of big data containing food records of general public users. We demonstrate that food intake trends have high correlation with the information trends of TV and social media. Based on the FoodLog platform, we collaborated with University Hospital, and we developed a new tool, FoodLog Athlete, that assists nutrition management and communication for sports dietitians and athletes. Thus, FoodLog is not only beneficial for healthcare purposes, but also for other applications, such as nutrition management for athletes.