The establishment and implementation of a healthy lifestyle is fundamental to public health and is an important issue for working-aged people, as it affects not only them but also the future generations. However, due to the COVID-19 pandemic and associated behavioural restrictions, lifestyles have altered, and, in certain environments, significantly worsened. In the present study, we conducted a project to improve the intestinal environment by focussing on the dietary habits of participants, utilising the living laboratory as a social technology to explore how to adapt to this drastic environmental change. We held eight workshops for voluntary participants and implemented a self-monitoring process of recording dietary behaviours (n = 78) and testing the intestinal environment (n = 14). Through this initiative, we developed a personalised wellness enhancement programme based on collaboration with multiple stakeholders and a framework for using personal data for research and practical purposes. These results provide an approach for promoting voluntary participation and behavioural changes among people, especially under the COVID-19 pandemic, as well as a practical basis for the government, academia, and industry to intervene effectively in raising people’s awareness of health and wellness.