Obesity is caused by various factors, including imbalance between energy intake and expenditure, sedentary lifestyle, genetics, and many other causes
[6]. In terms of cellular mechanisms, adipocytes (cells responsible for the storage of lipids from food and synthesized from de novo lipogenesis) and macrophages secrete adipokines, and excess secretion of adipokines causes low-grade inflammation in some obese people
[6][7]. In addition, triglycerides present in adipocytes hydrolyze into free fatty acids, and are transported into the blood circulation of obese people. Lipid deposition in hepatocytes can be seen in disease conditions such as non-alcoholic fatty liver disease (NAFLD) and other comorbidities related to obesity
[7]. Heymsfield and Thomas described how obesity is strongly connected to the pathogenesis of several chronic diseases, such as coronary artery disease (CAD), NAFLD, osteoarthritis (OA), gastroesophageal reflux disease, obstructive sleep apnea, stroke, and chronic kidney disease
[6]. Immune dysfunction derived from obesity is caused by excess secretion of inflammatory adipokines
[8]. A clinical study revealed that obesity was firmly connected with various proinflammatory cytokines, such as interleukins (ILs: IL-5, -10, -12, and -13), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α), and obese patients displayed elevated plasma levels of IL-4, -10, and -13
[9]. Thus, obesity is not simply a result of high energy intake and low energy expenditure; it is multifaceted, and inflammatory cytokines (increased TNF-α, IL-4, and IL-6; reduced IL-10), adipokines (e.g., adiponectin, leptin, resistin, and visfatin), and many other factors are involved in the pathogenesis of obesity
[10][11]. The interaction between adipocytes and hepatic lipid metabolism, along with imbalance in the synthesis of de novo synthesis, causes obesity and associated comorbidities
[12][13]. Adipocytes release adipokinomes or adipokines that control energy metabolism and dietary intake
[14]. Adipokinomes regulate the secretion of adipose cells, releasing fatty acids and prostaglandins, adipsin, proinflammatory cytokines such as IL-1β, -6, -8, and -10, and tumor necrosis factor-α (TNF-α)
[10][15][16]. Excess plasma IL-6 levels trigger the release of C-reactive proteins by hepatocytes, which indicate the levels of chronic inflammation and the risk of cardiovascular disorders
[17]. Collectively, these processes lead to lipid deposition (obesity), vascular hemostasis, insulin resistance, chronic metabolic diseases such as type 2 diabetes, and inflammation, as the proinflammatory cytokines transform into inflammatory cytokines
[17][18][19]. Inflammatory processes also stimulate the development or progression of psoriasis, cancer, and kidney diseases
[17]. Increased plasma contents of IL-6, IL-10, and IL-18 are observed among obese patients
[20][21]. Thus, obesity is not merely a metabolic disease; rather, it is a chronic inflammatory disorder, where dietary intake inflicts or triggers the pathogenesis of obesity and diabetes
[11][22].