The beneficial advantages of plant-based diets towards human beings have been well addressed over the last few decades. More and more people are now enjoying plant-based diets for their physical health, psychological health, animal rights, environment protection, etc. However, there are still many stereotypes about the lifestyle. Hence, this study aims at identifying key factors affecting the plant-based food choices so that we can propose feasible implications to widely promote plant-based diets across communities for their better health, eudemonic well-being and life satisfaction as well as the sustainable survival of our beloved planet—“Mother Earth”. Based on statistical analysis results of data collected from 1477 participants in 10 out of 19 provinces/cities in Southern Vietnam, the plant-based food choice is found significantly affected by not only gender and marriage status but also by a so-called SHOULD Model, where: (1) S refers to Spirituality and Social relationships; (2) H refers to Health concerns; (3) O refers to Opulence of plant-based foods and Outlook on life; (4) U refers to Understanding of human body structures; (5) L refers to Love towards animals; and (6) D refers to Diet knowledge. Among the identified factors, “understanding of human body structures” and “outlook on life” are two new factors proposed in this study, fulfilling the existing literature about the determinants of plant-based food choice. From such findings, some managerial implications are proposed to not only promote plant-based lifestyle but also help to develop plant-based food business in practice.