Persistent low-grade
inflammation, as indicated by higher circulating levels of inflammatory mediators such as
C-reactive protein,
interleukin-6 and tumour
necrosis factor-alpha, is a strong risk factor for several
chronic diseases. There are data indicating that decreasing energy intake and increasing physical activity may be effective
therapies for reducing overall
inflammation. Evidence is strong that circulating levels of inflammatory markers are elevated with total and
abdominal obesity, possibly owing to a higher secretion rate of
cytokines by adipose tissue in obese people. Moreover, very-low-energy dietary
weight loss reduces both circulating markers of
inflammation and adipose-tissue
cytokine production. Data from several large population-based cohorts show an inverse association between markers of systemic
inflammation and physical activity or fitness status; small-scale intervention studies support that exercise training diminishes
inflammation. Dietary
weight loss plus exercise is likely more effective than
weight reduction alone in reducing
inflammation. To date, data from randomized, controlled trails designed to definitively test the effects of
weight loss or exercise training, or both, on
inflammation are limited. Future studies are required to define the amount of
weight loss needed for clinically meaningful reductions of
inflammation; in addition, fully powered and controlled studies are necessary to clarify the effect of exercise training on chronic, systemic
inflammation.