Chronic inflammation, often driven by gut dysfunction rather than genetics, is linked to conditions like cancer, Parkinson’s, and autoimmune diseases. A compromised gut barrier—'leaky gut'—triggers immune activation and systemic inflammation, worsened by factors like antibiotics, alcohol, and poor diet. The gut microbiome plays a pivotal role in immune regulation, with fiber feeding beneficial bacteria that produce anti-inflammatory short-chain fatty acids like butyrate. Fermented foods and diverse plant-based eating boost microbial diversity, while trends like extreme restriction can do more harm than good. Early life, circadian rhythms, and even trauma impact gut health, with stress disrupting motility and barrier function. Practical steps—such as consistent meal timing, morning light exposure, and avoiding late-night eating—support gut recovery. Fecal transplants show promise for severe cases but aren't a substitute for long-term lifestyle changes. Ultimately, healing begins with fiber-rich nutrition, emotional well-being, and recognizing the gut as a foundational pillar of total health.