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With research staff from more than 60 countries, and offices across the globe, IFPRI provides research-based policy solutions to sustainably reduce poverty and end hunger and malnutrition in developing countries.

Erick Boy

researcher spotlight

Erick Boy

Erick Boy is the Chief Nutritionist in the HarvestPlus section of the Innovation Policy and Scaling Unit. As head of nutrition for the HarvestPlus Program since 2008, he has led research that has generated scientific evidence on biofortified staple crops as efficacious and effective interventions to help address iron, vitamin A, and zinc deficiency in sub-Saharan Africa, Latin America, and South Asia.

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experts

Nutrition, Diets, and Health

Jef L. Leroy

Senior Research Fellow

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Bio

Jef Leroy is a Senior Research Fellow in the Nutrition, Diets, and Health Unit, where he studies the impact of nutrition-sensitive agriculture and social protection programs on maternal and child nutrition. His evaluation studies use experimental designs combined with process evaluations and costing studies. Jef currently works on the evaluation of a social protection program in Bangladesh designed to improve birth outcomes and on the evaluation of a training and certification program aimed at improving the quality of milk sold by informal vendors in Nairobi. In addition, he studies the role of food environments in adolescent nutrition in urban areas in Ghana, Viet Nam, and Ethiopia and conducts research on child wasting and on the use of child linear growth in development.

Jef recently completed the evaluation of two large-scale food-assisted maternal and child health and nutrition programs in Burundi and Guatemala. His previous research focused on the impact of aflatoxin on child linear growth in Kenya and Mexico. Before joining IFPRI, Jef was a research associate in the Center for Evaluation Research and Surveys at Mexico’s National Institute of Public Health, where he worked on the evaluation of the urban and rural Oportunidades programs and of the Programa de Apoyo Alimentario (a cash and in-kind transfer program).

Jef, a Belgian citizen, has a PhD in international nutrition from Cornell University, US, and an MSc in agricultural and applied biological sciences from Ghent University, Belgium.

Languages: Dutch, English, French, Spanish

Google Scholar Profile

Google Scholar Citations

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Publications

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Journal Article

Accuracy of using weight and length in children under 24 months to screen for early childhood obesity: A systematic review

2025Boncyk, Morgan; Leroy, Jef L.; Brander, Rebecca L.; Larson, Leila M.; Ruel, Marie T.; Frongillo, Edward A.
Details

Accuracy of using weight and length in children under 24 months to screen for early childhood obesity: A systematic review

The global increase in early childhood overweight and obesity has prompted interest in early prediction of overweight and obesity to allow timely intervention and prevent lifelong consequences. A systematic review was conducted to assess the accuracy and feasibility of predicting overweight and obesity in individual three to seven-year-old children using data available in healthcare and community settings on children under 24 months of age. This review was registered in PROSPERO (CRD42024509603) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. From 7,943 unique articles identified through PubMed, CINAHL, Scopus, and Google Scholar, 14 studies met the inclusion criteria, 13 from high-income countries and one from a middle-income country. These studies evaluated the accuracy of predicting childhood overweight or obesity in individual children using anthropometrics-alone or multiple-predictor models. Anthropometrics-alone models yielded areas under the curve (AUCs) ≥0.56 with expert guidance and ≥0.77 with machine learning. Multiple-predictor models yielded AUC ≥0.68 with expert guidance and ≥0.76 with machine learning. The inclusion of child, parental, and community predictors improved predictive accuracy but led to greater variation in performance across models. Models were more accurate when children were older at the initial assessment, multiple assessments were made, and the time between assessment and outcome prediction was shorter. Prediction models with an AUC ≥0.70 used machine learning to optimize variable selection, limiting their practicality for broad-scale implementation in healthcare or community settings. There is insufficient evidence on the accuracy of overweight and obesity prediction models for children in low- and middle-income countries. Existing prediction models are not well-suited for broad-scale screening of individual children for risk of early childhood overweight or obesity.

Year published

2025

Authors

Boncyk, Morgan; Leroy, Jef L.; Brander, Rebecca L.; Larson, Leila M.; Ruel, Marie T.; Frongillo, Edward A.

Citation

Boncyk, Morgan; Leroy, Jef L.; Brander, Rebecca L.; Larson, Leila M.; Ruel, Marie T.; and Frongillo, Edward A. 2025. Accuracy of using weight and length in children under 24 months to screen for early childhood obesity: A systematic review. Advances in Nutrition 16(7): 100452. https://doi.org/10.1016/j.advnut.2025.100452

Keywords

Anthropometry; Children; Infants; Length; Obesity; Screening; Weight

Language

English

Access/Licence

Open AccessCC-BY-4.0

Links

https://doi.org/10.1016/j.advnut.2025.100452 Source record

Record type

Journal Article

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Book Chapter

Nutrition and diets: Research and action, looking back to move forward

2025Gillespie, Stuart; Ruel, Marie T.; Leroy, Jef L.; Olney, Deanna K.; Singhkumarwong, Anusara
Details

Nutrition and diets: Research and action, looking back to move forward

The last half-century has seen major changes in the nature of malnutrition around the world, as well as in our understanding of its manifestations and key drivers, the people most affected, and the policies and programs developed to address it. This chapter reviews the evolution of nutrition in both policy and programming, with particular attention to agriculture, food systems, and multisectoral approaches, before looking to future directions for nutrition policy, programming, and research. Book link: https://hdl.handle.net/10568/174108

Year published

2025

Authors

Gillespie, Stuart; Ruel, Marie T.; Leroy, Jef L.; Olney, Deanna K.; Singhkumarwong, Anusara

Citation

Gillespie, Stuart; Ruel, Marie T.; Leroy, Jef L.; Olney, Deanna K.; and Singhkumarwong, Anusara. 2025. Nutrition and diets: Research and action, looking back to move forward. In Global food policy report 2025: Food policy: Lessons and priorities for a changing world, eds. Johan Swinnen and Christopher Barrett. Part Four: Transforming Lives and Livelihoods, Chapter 12, Pp. 293-316. Washington, DC: International Food Policy Research Institute. https://hdl.handle.net/10568/174305

Keywords

Nutrition; Diet; Research; Nutrition Policies; Public Policies; Health; Food Systems; Nutrition-sensitive Agriculture

Language

English

Access/Licence

Open AccessCC-BY-4.0

Source

Source record

Record type

Book Chapter

Resource thumbnail

Journal Article

Adoption or placement in foster care and catch-up in linear growth and development: A meta-analysis of individual participant data

2025Leroy, Jef L.; Angel, Moira Donahue; Frongillo, Edward A.
Details

Adoption or placement in foster care and catch-up in linear growth and development: A meta-analysis of individual participant data

Background The ability of children to recover from linear growth retardation, often referred to as catch-up growth, has intrigued researchers for many decades. Whether adoption from a low-to a high-income setting, which provides a comprehensive improvement in the conditions that cause children to not grow well, leads to catch-up growth is unknown. Objective We estimated the association of adoption (or placement in foster care) with catch-up in linear growth and child development before 5 years of age. Methods We conducted a two-stage meta-analysis using individual participant data for linear growth. We obtained study-specific and subgroup estimates and pooled the estimates using random-effects models. Sensitivity analyses were used to assess the robustness of our findings. A review of child development outcomes was conducted. Results We included 485 children under 5 years of age from 9 adoption studies. At baseline, children had a mean age of 15.8 mo and a length deficit of 3.9 cm. Adoption reduced this gap by 77% or 3.0 cm (95% CI: 1.9-4.1 cm)(mean age 32.3 mo). Catch-up growth was found in both girls (3.6 cm; 95% CI 2.9-4.2 cm) and boys (2.5 cm; 95% CI: 1.9-3.1 cm) and in children adopted after the age of 24 mo (2.2 cm, 95% CI 0.6-3.7 cm). The sensitivity analyses did not change any of the substantive findings. The magnitude of catch-up in child development (mean reduction in deficit of 46%) was smaller than in linear growth. Conclusions Catch-up in linear growth in children under five is biologically possible when the environment is improved profoundly and comprehensively. Partial reversal of the accumulated height deficit was more likely than recovery in developmental outcomes which highlights the need to ensure all children grow and develop in environments that prevent deficits from occurring rather than trying to correct them.

Year published

2025

Authors

Leroy, Jef L.; Angel, Moira Donahue; Frongillo, Edward A.

Citation

Leroy, Jef L.; Angel, Moira Donahue; and Frongillo, Edward A. 2025. Adoption or placement in foster care and catch-up in linear growth and development: A meta-analysis of individual participant data. Advances in Nutrition 16(4): 100395. https://doi.org/10.1016/j.advnut.2025.100395

Keywords

Child Development; Children; Growth; Stunting

Language

English

Access/Licence

Open AccessCC-BY-4.0

Links

https://doi.org/10.1016/j.advnut.2025.100395 Source record

Project

Agriculture for Nutrition and Health

Record type

Journal Article

Blogs

What are kids watching online? How digital food marketing shapes children’s and adolescents’ diets
IFPRI Blog
 | 
April 03, 2025

What are kids watching online? How digital food marketing shapes children’s and adolescents’ diets

By Gabriela Fretes and Jef L. Leroy

A study shows the influence of social media.

Rethinking growth monitoring and promotion in low- and middle-income countries
IFPRI Blog
 | 
March 05, 2025

Rethinking growth monitoring and promotion in low- and middle-income countries

By Jef L. Leroy, Rebecca Brander, Edward A. Frongillo, Leila M. Larson, Marie Ruel, and Rasmi Avula

A study raises questions about a standard practice.

Evaluating impacts: Lessons from food systems interventions across Africa and Asia
IFPRI Blog
 | 
July 16, 2024

Evaluating impacts: Lessons from food systems interventions across Africa and Asia

By Jef L. Leroy, Lynnette Neufeld, Stella Nordhagen, and Sydney Honeycutt

Transforming food systems is promising but complex, requiring strong evidence and rigorous evaluations to ensure effective interventions.

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Events

23rd International Congress of Nutrition (ICN)
IFPRI at External Event

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August 24 to 29, 2025

23rd International Congress of Nutrition (ICN)

IFPRI is participating in the 23rd International Congress of Nutrition (ICN), hosted by the International Union of Nutritional Sciences (IUNS) on August 24-29 in Paris, France.  The theme of this year’s congress is “Sustainable Food for Global Health,” bringing together experts to discuss evidence and innovations in nutrition, sustainability, food science, and public health. IFPRI […]

10th annual Agriculture, Nutrition and Health (ANH) Academy Week
IFPRI Program/Country Event

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June 16 to 26, 2025

10th annual Agriculture, Nutrition and Health (ANH) Academy Week

IFPRI is participating in the 10th annual Agriculture, Nutrition and Health (ANH) Academy Week from June 16-26, 2025. The ANH Academy Week is a series of annual events that bring together the community of researchers, practitioners and policymakers working at the intersection of agriculture, food systems, nutrition and health. The objective of the ANH Academy […]

IFPRI @ CGIAR Science Week
IFPRI at External Event

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April 7 to 12, 2025

IFPRI @ CGIAR Science Week

When humanity has faced its greatest challenges, science and innovation have provided solutions. Today, major and connected global challenges threaten the sustainability of food, land, and water systems, with the most vulnerable people and communities at greatest risk. Recognizing the urgency of these challenges, CGIAR and the Kenyan Agricultural and Livestock Research Organization (KALRO) are […]

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News

February 20, 2025 | Press Release

New study challenges the use of Growth Monitoring and Promotion to detect growth faltering in children

A new study published in Advances in Nutrition critically examines the effectiveness of Growth Monitoring and Promotion (GMP) in diagnosing or screening for inadequate growth in children.

December 10, 2020 | In the News

Covid-19 and the irreversible marks undernutrition will leave in its wake (Poshan Outlook)

Poshan Outlook (India) published an op-ed by Poverty, Heath, and Nutrition Division Director Marie Ruel and Senior Research Fellow, Jef Leroy that stated one of the key objectives of India’s Covid-19 mitigation efforts is to prevent child undernutrition now rather than to treat it later, without compromising on maternal, child health and nutrition services. What started as a health crisis has developed into a […]

September 09, 2019 | In the News

Guatemalans grew an inch in half a century (Prensa Libre)

Guatemala’s Prensa Libre reported on the recent finding that Guatemalan women’s average height has increased an average of one centimeter over the past fifty years, making them the shortest female population in the world. The article explained the connections between stature and other indicators of health and quality of life and quoted Senior Research Fellow […]

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