The new coronavirus infection, the so-called covid-19, that raged around the world over the past 3 years or so has finally come to an end, human society seems to have resumed its normal precorona routine. However, this situation does not imply that we have eliminated this infectious disease, but rather that there is a strong possibility that this virus will mutate again and a second or third pandemic will occur in the future; in other words, we have entered an era of pandemics and thus must be aware of and prepare for the possible resurgence of similar pandemics to occur [1]. In the covid-19 pandemic, measures such as wearing masks, social distancing, city lockdown, and vaccinations have been proven to be reasonably successful 2, 3, 4, but it has also become apparent that people with so-called lifestyle-related diseases (LRD), such as diabetes, hypertension, hyperlipidemia, and arteriosclerosis, have a higher risk of serious illness and death 5•, 6, 7. Therefore, it is of paramount importance to reduce the number of people subject to LRD to minimize the impact of future pandemics. From this perspective, great expectations from human society are placed on the role of functional foods (FF) designed to prevent or alleviate LRD. In this review, we first discuss the problems associated with the conventional development process of FF, with specific reference to animal testing, and then describe the ‘human intestinal microbiota model’ constructed at Kobe University to solve these problems, and finally, typical examples of its use to contribute to the efficient development of FF that are effective in humans.