Original Article

International Journal of Obesity (2014) 38, 1511–1517; doi:10.1038/ijo.2014.52; published online 29 April 2014

Clinical Studies and Practice

Weight loss maintenance in overweight subjects on ad libitum diets with high or low protein content and glycemic index: the DIOGENES trial 12-month results

E E J G Aller1, T M Larsen2, H Claus3, A K Lindroos4, A Kafatos5, A Pfeiffer6, J A Martinez7,8, T Handjieva-Darlenska9, M Kunesova10, S Stender11, W H M Saris1, A Astrup2 and M A van Baak1

  1. 1Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
  2. 2Department of Nutrition, Exercise and Sports (NEXS), Faculty of Science, University of Copenhagen, Copenhagen, Denmark
  3. 3Institute of Preventive Medicine, Centre for Health and Society, Copenhagen, Denmark
  4. 4MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK
  5. 5Department of Social Medicine, Preventive Medicine & Nutrition Clinic, University of Crete, Heraklion, Greece
  6. 6Department of Clinical Nutrition, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuhetal, Germany
  7. 7Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
  8. 8CIBERObn, Instituto Carlos III, Madrid, Spain
  9. 9National Multiprofile Transport Hospital, Sofia, Bulgaria
  10. 10Obesity Management Centre, Institute of Endocrinology, Prague, Czech Republic
  11. 11Department of Clinical Biochemistry, Gentofte University Hospital, Hellerup, Denmark

Correspondence: Professor Dr MA van Baak, Department of Human Biology, NUTRIM School for Nutriton, and Toxicology and Metabolism, Maastricht University Medical Center+, PO Box 616, 6200 MD Maastricht, The Netherlands. E-mail: m.vanbaak@maastrichtuniversity.nl

Received 30 October 2013; Revised 26 February 2014; Accepted 17 March 2014
Accepted article preview online 28 March 2014; Advance online publication 29 April 2014





A high dietary protein (P) content and low glycemic index (LGI) have been suggested to be beneficial for weight management, but long-term studies are scarce.



The DIOGENES randomized clinical trial investigated the effect of P and GI on weight loss maintenance in overweight or obese adults in eight centers across Europe. This study reports the 1-year results in two of the centers that extended the intervention to 1 year.



After an 8-week low-calorie diet (LCD), 256 adults (body mass index >27kgm2) were randomized to five ad libitum diets for 12 months: high P/LGI (HP/LGI), HP/high GI (HP/HGI), low P/LGI (LP/LGI), LP/HGI and a control diet. During the first 6 months, foods were provided for free through a shop system and during the whole 12-month period, subjects received guidance by a dietician. Primary outcome variable was the change in body weight over the 12-month intervention period.



During the LCD period, subjects lost 11.2 (10.8, 12.0) kg (mean (95% confidence interval (CI))). Average weight regain over the 12-month intervention period was 3.9 (95% CI 3.0–4.8) kg. Subjects on the HP diets regained less weight than subjects on the LP diets. The difference in weight regain after 1 year was 2.0 (0.4, 3.6) kg (P=0.017) (completers analysis, N=139) or 2.8 (1.4, 4.1) kg (P<0.001) (intention-to-treat analysis, N=256). No consistent effect of GI on weight regain was found. There were no clinically relevant differences in changes in cardiometabolic risk factors among diet groups.



A higher protein content of an ad libitum diet improves weight loss maintenance in overweight and obese adults over 12 months.


body weight changes; dietary proteins; glycemic index; risk factors

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