Prevention of Diabetes through Lifestyle Intervention in Europe and Australasia (PREVIEW)
Posted On: 25th November 2020
Weight reduction and maintenance, along with increased physical activity are key elements of type 2 diabetes prevention. No-one disputes this, but the best way to lose and maintain weight and maintain higher levels of physical activity is not clear.
With the impressive results from the Diabetes UK funded DiRECT trial (see Lean MEJ et al) there is increasing acceptance of the use of Total Diet Replacement (TDR) with formula diet to achieve an initial weight loss of 10-15kg. There is also evidence from the DiOGenes trial that after an initial TDR weight loss a higher protein and lower glycaemic index (GI) diet gave better weight maintenance at six months than a moderate protein, higher GI diet (see Larsen TM et al). It was logical to repeat the DiOGenes diet in those with prediabetes to determine whether a higher protein, lower carbohydrate and lower GI diet after a TDR weight loss would deliver a reduced rate of conversion to diabetes.
More than 2200 people with pre-diabetes based in six EU countries as well as Australia and New Zealand took part. Average baseline weight was 100kg (1504 women mean weight 96kg, 720 men mean weight 109kg). An 800kcal/d low energy diet of formula foods was given to all participants regardless of individual energy requirement. Two thousand and twenty individuals (91%) completed the eight-week diet. Women lost an average 10.2kg and men an average 11.8kg. Mean fat free mass loss was proportionately greater in women at 3.2kg, than in men at 1.9kg and the authors wondered if this may influence the outcome of weight maintenance. 35% of participants with impaired fasting glucose reverted to normo-glycaemia after weight loss (see Christensen P et al).
Those who lost 8% or more of their initial weight during the ‘pre-randomisation’ weight loss phase followed one of two diets, either a higher protein (25% energy), lower carbohydrate (45% energy), lower GI (<50) diet or moderate protein (15% energy), higher carbohydrate (55% energy) and higher GI (>56) diet and one of two exercise programmes: moderate physical activity or higher physical activity. Participants were seen monthly up to six months then with decreasing frequency as time progressed towards the 3 year end point.
Compliance with the dietary programme was good and reasonably consistent throughout but was not quite up to the targets set. At year three differences between the groups were only 9g for protein and 3.3 units for GI though glycaemic load (GI x g carbohydrate daily) was 13.6 units different. Dietary energy consumption, from diet records, at three years was about 2000kJ less in both dietary groups from baseline values around 8800kJ/d on average. Drop out from the maintenance programme was 26%, 15% and 7% during years 1, 2 and 3, suggesting that the maintenance intervention needed extra measures especially immediately after the initial weight loss.There was no significant difference between the four groups at 3 years in terms of weight maintenance which ranged from 4.6 to 4.9kg weight loss maintained. This represented around 57-46% of weight loss maintained on average (see Raben A et al).
By the end of 3 years 62 participants had developed type 2 diabetes (3.3% of 1857 who started but 6.4% of 962 completers) a lower number than was expected based on three-year results in other diabetes prevention studies. Three-year changes in body weight were significantly correlated with fasting glucose, 2h glucose, insulin and HbA1c but no numerical details were given. Despite highlighting the different fat free mass losses in men and women following TDR initially, results for men and women were not presented separately for the three-year maintenance programme.
This paper suggests that an initial large weight loss with TDR may help reduce risk of developing type 2 diabetes. The study did not demonstrate that higher protein lower GI diets are more effective than lower protein higher GI diets in this design and setting, however further examination of compliant versus less compliant participants may reveal some variations in their responses. In the DiRECT study greater weight loss and better weight maintenance was associated with remission and better metabolic responses. In the PREVIEW study 200 participants maintained more than 10% weight loss for three years. More details of how those who maintained more weight loss compared to those who maintained less weight loss differed metabolically at three years is eagerly awaited.
Anthony R Leeds
Lean MEJ etal Durability of a primary care-led weight-management intervention for remission of type 2 diabetes: 2-year results of the DiRECT open-label, cluster-randomised trial. Lancet Diabetes and Endocrinology 2019; 7 (5): 344-355. https://www.thelancet.com/journals/landia/article/PIIS2213-8587(19)30068-3/fulltext
Larsen TM et al Diets with high or low protein content and glycemic index for weight-loss maintenance N Engl J Med 2010;363(22):2102-13. doi: 10.1056/NEJMoa1007137.
Christensen P et al Men and women respond differently to rapid weight loss: Metabolic outcomes of a multi-centre intervention study after a low-energy diet in 2500 overweight, individuals with pre-diabetes (PREVIEW) Diabetes Obes Metab. 2018;20: 2840–2851 https://doi.org/10.1111/dom.13466
Raben A et al The PREVIEW intervention study: Results from a 3-year randomized 2 x 2 factorial multinational trial investigating therole of protein, glycaemic index and physical activity for prevention of type 2 diabetes. Diabetes Obes Metab. 2020;1 –14. doi:10.1111/dom.14219 October 2020
The PREVIEW study was funded by the EU Framework programme 7, Grant/Award Number: 312057 and other agencies see https://dom-pubs.onlinelibrary.wiley.com/doi/epdf/10.1111/dom.14219 and Cambridge Weight Plan Ltd, Northants, UK provided product (gratis) for the initial 800kcal/d weight loss phase.