Stress is a biological state in which the body responds to perceived physical, emotional, metabolic, or environmental demand through coordinated nervous, hormonal, inflammatory, and metabolic signaling. The central stress response begins in the brain, especially the hypothalamus and limbic system, which communicate with the autonomic nervous system and the hypothalamic-pituitary-adrenal axis. Acute stress can increase alertness, heart rate, blood pressure, glucose release, and immune signaling. When stress becomes frequent or prolonged, the same systems can remain activated longer than intended, contributing to fatigue, poor sleep, digestive discomfort, headaches, irritability, blood sugar swings, cravings, muscle tension, and reduced concentration. Stress biology is strongly connected to cortisol rhythm, norepinephrine and epinephrine signaling, inflammatory cytokines, oxidative stress, mitochondrial energy demand, endothelial function, gut-brain communication, and circadian rhythm regulation. Diet composition can influence stress-related physiology through several measurable pathways. Whole plant foods provide complex carbohydrates that support steady glucose delivery, fiber that supports gut microbial short-chain fatty acid production, potassium and magnesium that participate in nerve and muscle function, vitamin C and polyphenols that support antioxidant defenses, and folate/B vitamin pathways that participate in one-carbon metabolism and neurotransmitter synthesis. Highly refined foods, excess sodium, added sugars, alcohol, stimulant overload, and low-fiber dietary patterns are associated with less favorable metabolic and inflammatory profiles. A P53 whole-food plant-based pattern emphasizes intact fruits, vegetables, legumes, whole grains, mushrooms, nuts, seeds, herbs, and spices while avoiding oils, meat, dairy, and toxin-associated dietary exposures. In stress support, the focus is not sedation or masking symptoms; it is biological support for steady energy, antioxidant capacity, hydration, mineral balance, gut microbiome signaling, endothelial function, and circadian meal timing. Key plant foods such as oats, brown rice, lentils, chickpeas, black beans, spinach, kale, broccoli, berries, citrus, flax, chia, pumpkin seeds, and green tea provide fiber, minerals, vitamins, amino acids, and phytochemicals relevant to stress-response biology. This database entry organizes stress as an ailment pattern linked to HPA axis signaling, catecholamine turnover, oxidative stress, inflammatory signaling, glucose regulation, gut-brain communication, and sleep-wake rhythm support through 100% whole-food plant-based nutrition.