Southern-Style Mediterranean Diet Matches WeightWatchers, Trial Finds

A Mediterranean-style eating plan adapted to Southern food preferences produced about as much weight loss as WeightWatchers over two years, but led to substantially greater improvements in diet quality, according to a randomized clinical trial led by researchers at the University of North Carolina at Chapel Hill. The findings, from a study called DELISH (Delicious Eating for Life in Southern Homes), were published in JAMA Network Open.

The study tested whether a culturally adapted Mediterranean-style diet could support weight loss while also addressing cardiovascular disease risk in the southeastern United States, where communities experience a greater burden of chronic diseases including diabetes, stroke and cardiovascular disease. The researchers developed the Med-South Weight Loss Program, which follows Mediterranean dietary principles — emphasizing healthy fats, fruits, vegetables, beans, nuts and fish while limiting sugary drinks, sweets and processed meats — but adapts them to Southeastern foods and tastes, including peanuts, collard greens, barbecue and modified hush puppies.

The trial enrolled 360 adults with a body mass index of 30 or higher, recruited from primary care practices in central North Carolina, who were randomly assigned to either the Med-South program or a control program using WeightWatchers. Med-South participants moved through three phases over 24 months, focused first on improving diet quality, then on weight loss while maintaining the Med-South eating pattern, and finally on maintaining the weight they had lost. Researchers measured body weight, diet quality and blood pressure at 4, 12 and 24 months, assessing diet quality partly through a device called the Veggie Meter, which measures skin carotenoid levels that correlate with fruit and vegetable intake.

After 24 months, participants in both groups had lost weight and maintained the loss, with an average reduction of about 4.5 kilograms, or roughly 10 pounds, among those who returned for follow-up; the researchers found no significant difference between the two programs in weight loss or blood pressure change. The groups differed more clearly in diet quality: Med-South participants reported substantially better dietary patterns, including greater consumption of high-quality fats and lower carbohydrate intake, along with higher overall diet quality scores, while Veggie Meter scores improved in both groups.

"Incorporating a healthful dietary pattern into lifestyle weight loss programs should be a priority," said Thomas Keyserling, a co-principal investigator and professor at the UNC School of Medicine. "While similar weight loss can be achieved with calorie-restricted diets, there are added benefits to chronic disease prevention associated with a healthful dietary pattern."