All four diets, which also included the Atkins Diet and Rosemary Conley's "Eat Yourself Slim" Diet & Fitness Plan, helped people lose more weight than people who ate normally, the study found.
There was no significant difference between the diets in how much weight people lost, Helen Truby of Royal Children's Hospital in Australia and her British colleagues reported in BioMed Central's Nutrition Journal.
"Health professionals and those working in community and public health should be reassured of the nutritional adequacy of the diets tested," the researchers wrote.
Truby and colleagues asked 293 people on diets across Britain to record how much food they ate during a two-month period and compared the results with a group who ate normally.
They found that all four diets led to weight loss, but that only people on the Weight Watchers plan boosted the amount of fruit and vegetables they ate, even though the other plans also advised people to do so.
"These disappointing findings suggest that people remain resistant to the advice to 'eat more fruit and vegetables'," Truby said in a statement. - (Reuters Health)
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