TNF and obesity due to melanocortin 4 receptor deficiency: Chronic conditions such as CVD, diabetes, obesity, rheumatoid arthritis, and IBD are all associated with increased production of PGE2, LTB4, TXA2, IL-1β, IL-6, and TNF-α, whereby the production of these factors increases with increased dietary intake of n-6 PUFA and decreased dietary intake of n-3 PUFA.