The concept of the metabolic syndrome, although controversial, continues to gain acceptance. Whereas each risk factor of the metabolic syndrome (visceral obesity, atherogenetic dyslipidemia, elevated blood pressure, and dysglycemia) can be dealt with individually, the recommended initial therapeutic approach is to focus on reversing its root causes of atherogenetic diet, sedentary lifestyle, and overweight or obesity. No single diet is currently recommended for patients with the metabolic syndrome, although epidemiologic evidence suggests a lower prevalence of the metabolic syndrome associated with dietary patterns rich in fruit, vegetables, whole grains, dairy products, and unsaturated fats. We conducted a literature search to identify clinical trials specifically dealing with the resolution of the metabolic syndrome by lifestyle, drugs, or obesity surgery. Criteria used for study selection were English language, randomized trials with a placebo or control group (except for surgery), a follow-up lasting>or=6 mo, and a time frame of 5 y. We identified 3 studies based on lifestyle interventions, 5 studies based on drug therapy, and 3 studies based on laparoscopic weight-reduction surgery The striking resolution of the metabolic syndrome with weight-reduction surgery (93%) as compared with lifestyle (25%) and drugs (19%) strongly suggests that obesity is the driving force for the occurrence of this condition. Although there is no "all-inclusive" diet yet, it seems plausible that a Mediterranean-style diet has most of the desired attributes, including a lower content of refined carbohydrates, a high content of fiber, a moderate content of fat (mostly unsaturated), and a moderate-to-high content of vegetable proteins.