The investigators recent epidemiologic work in several national surveys and cohorts of men and women have shown that dietary patterns high in plant-based foods and phytochemicals are associated with lower plasma levels of insulin, triglycerides, and C-reactive protein, and reduced risk of type 2 DM and CHD. While the physiologic impact of different foods on serum glucose and insulin is of critical importance, the extent to which specific dietary nutrients can modify insulin resistance is not well understood. Magnesium is a biologically active constituent in whole-grain, green leafy vegetables, and nuts and appears to play an essential role in hundreds of physiologic processes in humans. However, it remains uncertain whether magnesium intake can exert effects on insulin sensitivity and inflammation. Moreover, little is known of the extent to which magnesium intake elicits changes in the expression levels of key genes responsible for glucose homeostasis and systemic inflammation. The ultimate clinical question is whether magnesium supplementation would be clinically effective for the improvement of metabolic disorders in not yet diabetic but high-risk individuals, especially those who are susceptible to insulin resistance. Therefore, as a direct follow up on our previous work in studying the health benefits of plant-based foods such as whole grains, fruits and vegetables, we propose a pilot randomized trial to unravel the metabolic and anti-inflammatory effects of magnesium supplementation versus placebo among overweight individuals with the metabolic syndrome who are particularly prone to the adverse effects of magnesium deficiency. Recent advancements in molecular genetics and genomic technologies have also enabled us to analyze the expression levels of thousands of genes simultaneously in different experimental conditions. The application of high throughput microarray technology in randomized-controlled setting when analyzed with novel statistical methods, will not only help our understanding of nutrient-disease relations, but also afford the investigators the opportunity to gain important insight into the molecular mechanism for complex biological systems of inflammation, insulin resistance, and metabolic abnormalities in response to nutrition intervention.