Acknowledgements The World Health Organization(WHO)would like to thank author of this paper,Dr Helene Delisle, Professor,Department of Nutrition,Faculty of Medicine,University of Montreal,Canada. Special thanks also go to Dr B.De Benoist of the WHO Department of Nutrition for Health and Development (NHD)for his valuable contributions to the revision and finalization of the paper,and Ms D.Klinger of the Department of Child and Adolescent Health and Development(CAH)for editing it.Many thanks also go to the WHO regional advisors on adolescent health and development from WHO AFRO,AMRO,EMRO,EURO,SEARO,and WPRO regional offices. Acknowledgement is also made of the contributions of(in alphabetical order):Dr A.Pradilla,Universidad del Valle,Colombia;Dr J.Rivera-Dommarco,Instituto Nacional de Salud Publica,Mexico;Dr R.Solon, Nutrition Center of the Philippines,Philippines;and Dr.R.Uauy,Instituto de Nutricion y Technologicas de la Alimentos,Chile,who acted as external reviewers.Acknowledgement is also made of the coordinating roles played by Dr V.Chandra-Mouli,Ms J.Ferguson,and Dr A.Olukoya of CAH. vi/vi/ Acknowledgements The World Health Organization (WHO) would like to thank author of this paper, Dr Hélène Delisle, Professor, Department of Nutrition, Faculty of Medicine, University of Montreal, Canada. Special thanks also go to Dr B. De Benoist of the WHO Department of Nutrition for Health and Development (NHD) for his valuable contributions to the revision and finalization of the paper, and Ms D. Klinger of the Department of Child and Adolescent Health and Development (CAH) for editing it. Many thanks also go to the WHO regional advisors on adolescent health and development from WHO AFRO, AMRO, EMRO, EURO, SEARO, and WPRO regional offices. Acknowledgement is also made of the contributions of (in alphabetical order): Dr A. Pradilla, Universidad del Valle, Colombia; Dr J. Rivera-Dommarco, Instituto Nacional de Salud Publica, Mexico; Dr R. Solon, Nutrition Center of the Philippines, Philippines; and Dr. R. Uauy, Instituto de Nutricion y Technologicas de la Alimentos, Chile, who acted as external reviewers. Acknowledgement is also made of the coordinating roles played by Dr V. Chandra-Mouli, Ms J. Ferguson, and Dr A. Olukoya of CAH