Possible physiological benefits of fasting and exercise.

Exercise and fasting, by activating hypothalamic neurons, lead to appetite regulation, increased energy efficiency, increased brown fat cells, and weight loss. Additionally, fasting and exercise affect brain plasticity and cognitive function by reducing oxidative brain damage and increasing brain-derived neurotrophic factor (BDNF), potentially reducing the risk of neurological diseases. In humans, these lifestyle interventions can also modulate autophagy and apoptosis in lymphocytes, especially natural killer (NK) cells, T cells, and B cells, which play an important role in fighting cancer and virus-infected cells. Fasting and exercise increase the concentration of autophagic monocytes, enhance killer T lymphocytes, strengthen the immune system, and delay cancer progression. Fasting and exercise can improve metabolic and inflammatory parameters through immune-related molecules, reducing systemic inflammation. Furthermore, they are associated with changes in the composition and function of gastrointestinal microbes, including an increase in beneficial microbes and a decrease in pathogenic bacteria, along with intestinal epithelial integrity.