CoMFORT (Cow’s Milk Fat Obesity pRevention Trial)

This project is part of TARGet Kids! (The Applied Research Group for Kids).

In Progress

Child and Youth Health

Poor nutrition can lead to long-term physical and mental-health problems, such as obesity, behaviour problems and poor school performance. These issues further widen the social, educational and economic divide.

Children living in low-income households are at highest risk of childhood obesity and its long term cardiovascular consequences. Given that most children in North America consume cow’s milk daily, understanding which milk fat minimizes the risk of childhood obesity is an essential and actionable step in reducing childhood obesity.

Every parent wants to know which type of milk is best for their child. Before this study, no one knew the answer to this simple question. Unlocking this answer will lead to far-reaching results as children grow and develop.

Which milk fat content is best for children’s growth and development?

To find out, we conducted a randomized controlled trial of 534 healthy two-year olds, across 12 primary care practices in low-income Toronto neighborhoods.

Children were randomized into two groups. One group received a recommendation to consume whole (3.25% fat) milk, and the other group received a recommendation to consume reduced-fat (1% fat) milk (consistent with standard of care). The recommended amount of milk for both groups was 500mL every day.

When the children turned four, we measured their Body Mass Index z-score (zBMI) using the World Health Organization (WHO) growth standards. We also assessed their development using the Ages and Stages Questionnaire and the Early Development Instrument, serum lipids and vitamin D concentrations, and sugar-sweetened beverage and total caloric intake measured using the ASA24 dietary recall tool.

We analyzed all this information to determine whether a whole milk vs. reduced fat milk recommendation at age two years can: 1) reduce/prevent obesity, 2) lower cardiovascular risk factors, 2) improve child development, 4) increase vitamin D stores, and 5) lower sugar sweetened beverage consumption and total caloric intake at four years of age.

The results will help policy makers, clinicians and families make decisions about milk, an important determinant of the weight and subsequent health of children. Results from this trial will be applicable to nutrition practice and policy because: 1) Two widely accepted, clinically relevant alternatives will be directly compared; 2) A diverse sample of healthy low-income children are involved; 3) Important health outcomes will be measured including adiposity, child development, and nutrition; and 4) The team includes motivated clinicians, parents, and policymakers from multiple scientific institutes across Canada as well as influential public-health and primary-care organizations.

Parents of children participating in TARGet Kids! contributed to all aspects of this pragmatic, patient-oriented, randomized, controlled clinical trial, including study design and communication of results to families in their communities.

Learn more at

Child and Youth Health

Dr. Jonathon Maguire

Dr. Jonathon Maguire believes that by focusing on the factors that foster resilience, we can help our children lead healthier, happier lives. He is a hospital pediatrician and the co-leader of TARGet Kids!, the largest primary-care research network for children in Canada.


  • Mary Aglipay (St. Michael’s Hospital)
  • Dr. Catherine Birken (SickKids)
  • Dr. Evelyn Constantin (McGill University)
  • Dr. Magdalena Janus (McMaster University)
  • Dr. Peter Jüni (St. Michael’s Hospital)
  • Dr. Mary L’Abbe (University of Toronto)
  • Dr. Andreas Laupacis (St. Michael’s Hospital)
  • Dr. Patricia Li (Montreal Children’s Hospital)
  • Dr. Deborah O’Connor (University of Toronto)
  • Dr. Jessica Omand (Postdoctoral Fellow
  • Dr. Patricia Parkin (SickKids)
  • Dr. Clare Relton (Queen Mary University
  • Dr. Kevin Thorpe (St. Michael’s Hospital)
  • Shelley Vanderhout (St. Michael’s Hospital)
  • Dr. Peter Wong (SickKids)
  • Shannon Weir (parent)
  • Erika Tavares (parent)


  • CIHR Strategy for Patient Oriented Research


  • Joannah and Brian Lawson Centre for Child Nutrition
  • Maternal, Infant, Child and Youth Research Network
  • Canadian Pediatric Society
  • Public Health Agency of Ontario
  • Section of Community Pediatrics, SickKids
  • Ontario Child Health Support Unit
  • Ontario Medical Association

Contact Info

Dr. Jonathon Maguire

Principal Investigator