Ulcerative colitis is a chronic inflammatory bowel condition centered in the inner lining of the colon and rectum. During active periods, the intestinal lining can show immune-cell infiltration, epithelial injury, ulceration, oxidative stress, mucus barrier disruption, altered microbial balance, and increased inflammatory signaling. During remission, symptoms may be reduced or absent, but the biological focus remains support of epithelial barrier integrity, balanced immune activity, healthy short-chain fatty acid production, and steady bowel function. A whole-food plant-based pattern can support remission biology by emphasizing soluble fiber, resistant starch, polyphenols, carotenoids, vitamin C-rich foods, magnesium-rich foods, potassium-rich foods, and diverse fermentable carbohydrates that gut bacteria can convert into short-chain fatty acids such as butyrate. Butyrate is used by colonocytes as an energy source and is involved in epithelial barrier maintenance, mucin production, immune regulation, and inflammatory signaling control. Plant foods also provide antioxidant compounds that interact with NF-κB, Nrf2, cytokine signaling, oxidative stress pathways, and gut microbial metabolism. Foods such as oats, brown rice, lentils, blueberries, pomegranate, broccoli, spinach, sweet potato, flax seeds, turmeric, ginger, and green tea provide fiber, polyphenols, flavonoids, glucosinolates, carotenoids, minerals, and plant compounds connected in research to gut barrier and inflammatory biology. A remission-support approach is not built around oils, meat, dairy, alcohol, additives, or highly processed foods. It is centered on gentle, well-cooked, blended, peeled, or softened whole plant foods when needed, with gradual fiber progression based on tolerance. Because ulcerative colitis can vary by severity, location, bowel pattern, and food tolerance, the biological goal is to support a calmer mucosal environment, a more stable gut microbiome, antioxidant defense, hydration, electrolyte balance, and nutrient sufficiency without irritating the digestive tract. P53 Nutrition frames this condition through food-to-pathway mapping, focusing on plants that support gut microbiome signaling, SCFA signaling, epithelial barrier integrity, Nrf2 antioxidant response, NF-κB regulation, immune response signaling, glutathione defense, and hydration-electrolyte balance during remission support.