Over the past two years, the world’s population has been tested by the COVID-19 health emergency. This has changed population habits worldwide by encouraging a sedentary lifestyle and overnutrition. Isolation and reduction of social life, for most of the population, was mandatory but it quickly became a new lifestyle. Nowadays, we are encountering the consequences with an increase in nutritional associated disorders and conditions that cause illnesses in the general population. These disorders include diet excesses that lead to obesity and diet deficiencies and malnutrition which could rapidly lead to death. These eating disorders are very complex to manage because they become mental disorders which can negatively impact physical or mental health. This work will disucss the benefits associated with the mindfulness–exercise–nutrition (MEN) technique. From a nutritional point of view it will focus on the nutritional effect of a plant-based diet, such as the Mediterranean diet (MD) which has a high tryptophan content which can increase serotonin (the “feel good” hormone) levels. The MEN technique takes a multidisciplinary approach and aims to integrate healthy behaviors into clinical practice using healthy eating, active living, and mindfulness. This method includes controlled physical movements, stretching techniques such as yoga, and aerobic exercise to achieve optimal mental and physical health. This literature review, carried out using the PubMed, ScienceDirect, Scopus, and Google Scholar databases, aims to investigate the latest research on this topic. This study may be useful for healthcare professionals and clinicians and may help patients to be more self-aware, encouraging them to lead a healthier lifestyle, make thoughtful choices, and ameliorate their mental health. The final aim of this study is to promote physiological homeostasis and well-being.