The three-year multi-centre randomised controlled trial was conducted in eight countries (Denmark, Finland, the Netherlands, the UK, Spain, Bulgaria, Australia and New Zealand), starting with an eight-week weight reduction phase, followed by a three-year weight maintenance phase.
In the first phase, participants had to achieve a weight loss of eight percent or more using total meal replacements. In total 2,326 overweight or obese adults aged 25-70 years with pre-diabetes were enrolled.
Ninety seven percent of trial graduates who had achieved the required fast weight loss had not developed diabetes by the end of the three-year trial.
Professor Brand-Miller highlights: “The most important finding in PREVIEW was the low incidence of diabetes in all groups at the end of the study.”
Just 62 participants developed type 2 diabetes, giving a cumulative incidence of only one per 100 person-years. This compared with about five per 100 person-years in the diet arm of a 2002 Diabetes Prevention Study in the United States. In that study, participants had slower weight loss over a longer timeframe.
In the PREVIEW study, no differences were found between the two diets or the two physical activity programs, although fewer participants in the high protein groups achieved normal glucose status. With such a low incidence of diabetes, the researchers did not have the ability to detect any difference between the diet or physical activity arms. It is also important to note they did not have an untreated control group.