Gut microbiota refers to the bacterial communities in the gastrointestinal tract. The diversity and quantity of bacteria vary depending on age of the individuals, daily diet and the segment of the intestine, which makes the gut microbiota one of the most complex bacterial ecosystems known to men. In general, over trillions of bacteria reside in human gut. Recent evidence indicates that gut microbiota could be involved in host metabolism by multiple pathways leading to the development of obesity and type 2 diabetes. Increased fat storage or obesity has become one of the leading public health issues in many developed and developing countries. However, it is not clear whether type 2 diabetes is associated with a unique gut microbiota profile. Therefore, the primary objective of the study is to compare the fecal microbiota of overweight type 2 diabetic subjects to that of age, gender and BMI matched subjects as well as with lean non-diabetic subjects. In addition, the investigators hypothesize that microbiota modifications with consumption of fiber rich food products can improve the metabolic outcomes of type 2 diabetics. To test this hypothesis, the investigators plan to provide each overweight participant with two cereal bars per day for 4 weeks. Anthropometric measurements and plasma parameters as well as the fecal microbiota will be determined.