Modifiable lifestyle factors, like nutrition, significantly impact conditions such as knee and hip osteoarthritis (OA), but are often neglected in favor of physical activity, medications, and procedural treatments. Certain fruits and vegetables can reduce oxidative stress and help maintain homeostatic levels of various inflammatory markers, leading to slower progression of knee and hip OA. Meat and dairy intake have been shown to have varying effects on knee and hip OA symptoms depending on the type and quantity of intake. Supplements such as collagen, glucosamine, krill oil, and chondroitin can improve OA-related pain and have been suggested to improve cartilage integrity. Although numerous studies on these foods and supplements have demonstrated clinical improvements in OA symptoms, reductions in inflammatory biomarkers, and indications of cartilage maintenance, there remains a lack of large-scale trials that firmly connect the proposed physiological mechanisms to clinical outcomes. Further research should help elucidate more of these biochemical pathways in relation to improving pain and function in OA.