The approach that I use is a low carbohydrate/ketogenic diet. In my view, the primary benefits of this approach are that 1) it results in reliable/relatively rapid weight loss without hunger or necessity for calorie counting, 2) it minimizes carb cravings/sweet tooth and thus facilitates a transition to eating real, non-processed food, and 3) it directly addresses what is in my view the root cause of metabolic syndrome - carbohydrate intolerance and resultant insulin resistance (not fat gain - it is complicated, but I think it is more correct to view the fat gain as an effect rather than a root cause of metabolic syndrome.)
I highly recommend two books for interested providers and patients. First is "A Low Carbohydrate, Ketogenic Diet Manual: no Sugar, No Starch Diet," by Eric C. Westman, M.D.. Dr. Westman is the clinical expert on the use of well formulated low carbohydrate diets for the treatment of obesity and metabolic syndrome. This pamphlet is the instructional manual for the approach that he uses. Dr. Westman's approach served as the model for my own and I consider him a mentor.
The second book that I recommend is "The Art and Science of Low Carbohydrate Living: An Expert Guide to Making the Life-Saving Benefits of Carbohydrate Restriction Sustainable and Enjoyable." by Jeff S. Volek, Ph.D.,R.D., and Stephen D. Phinney, M.D., Ph.D.. This is an extremely readable but still scientific and detailed guide to why carbohydrate restriction is such a powerful and beneficial intervention for many of our patients.