Obesity is associated with sub-clinical chronic oxidative and inflammatory stress, both of which are major contributors to obesity-associated co-morbidities. Calcitriol (1, 25-(OH)2-D3) regulates adipocyte lipid metabolism, while dietary calcium inhibits obesity by suppression of calcitriol. We have recently shown calcitriol to increase oxidative stress and to stimulate the expression and release of inflammatory cytokines, while inhibiting the expression and release of anti-inflammatory cytokines. We have also shown that inhibition of calcitriol with high calcium diets decreases both adipose tissue and systemic oxidative and inflammatory stress in a mouse model of obesity. Moreover, dairy exerted a greater effect on both oxidative and inflammatory stress. These mice also exhibited significant reductions in adiposity, which could lead to confounding, as this reduction will independently reduce oxidative and inflammatory stress. However, the supporting cellular/mechanistic data indicate an effect which is independent of adiposity reduction. Consequently, we propose that low calcium diets exacerbate oxidative and inflammatory stress and that high dairy diets can attenuate both independently of changes in adiposity, thereby significantly reducing the risk of obesity-associated co-morbidities. Accordingly, the objective of this study is to determine the acute effects of a dairy-rich diet on oxidative and inflammatory stress in overweight and obese subjects in the absence of any changes in adiposity.