The purpose of this research is to assess the effects of a low-carbohydrate (modified Atkins) diet versus a low fat (Heart Healthy) diet on cardiovascular health.

The purpose of this study is to compare the effects of a modified Atkins diet (low carbohydrate and low calorie) and a traditional heart healthy diet (low fat and low calorie) on biochemical markers of inflammation and metabolism, anthropometric measurements, vascular studies of endothelial function, adipose tissue composition, and patient compliance and satisfaction over a twelve week period in healthy men and women. Patients will be recruited from the Nutrition and Weight Management Center at Boston Medical Center. Enrolled subjects will be randomly assigned to a reduced calorie diet (either the Atkins diet or a traditional heart healthy diet), and will be counseled by a dietitian and a physician throughout the study period. The patients will have physical exams, labs, vascular studies of endothelial function, and adipose tissue biopsies at baseline and at twelve weeks to assess progress. Participants dietary compliance will be assessed using food journals and 24 hour recall.

The Atkins diet appears to have potential to reverse the epidemic of obesity-linked cardiovascular disease (CVD) in the United States. Obesity is in effect an inflammatory state in which adipose (fat) tissue releases adipokines- small, inflammatory proteins. High adipokine levels in the blood lead to an inflammatory response, ultimately damaging the endothelial cells which line the blood vessels and increases the risk of vascular disease. Ultimately the effects of these two different diets will be analyzed to help determine if a low carbohydrate, low calorie diet is more beneficial than a traditional heart healthy diet (low fat, low calorie) at reducing the systemic inflammatory response by using physical exam measures, inflammatory blood markers, vascular ultrasound studies, and adipose tissue biopsies.

Inclusion Criteria:

• Age 18-65 years
• BMI greater than or equal to 30

Exclusion Criteria:

• Currently pregnant or lactating
• Type 2 diabetes
• Use of oral anti-diabetes medications (with exception of Metformin for control of PCOS)
• Presence of known peripheral arterial or cardiovascular disease
• Change in body weight (greater or equal to 3% within the past 3 months)
• Recent use (within the four weeks prior to screening) of weight loss medications including but not limited to phentermine, sibutramine, orlistat, or over the counter weight loss products
• History of an eating disorder or significant disordered eating behaviors such as binging/purging, abuse of laxatives or diuretics
• History of established renal or hepatic disease
• History of prior bariatric surgery
• Subjects who report routine tobacco use
• Subjects on Angiotensin receptor blockers (medications such as but not limited too Adicant, Losartan, Avapro, Diovan, Micardis, Teveten, Candesarten/thiazide, Ibesarten/thiazide, Valsartan/thiazide, Losarten/thiazide, Telmisarten/thiazide, Teveten/thiazide