Milk-Tot Study: Impact of Whole Versus Low-fat Milk on Child Health

Milk Type in Toddlers (Milk-TOT) Study: Impact of Whole Versus Low-fat Milk on Child Adiposity, Health and Development

In the U.S. it is recommended that children consume whole cow's milk (3.5% fat) from ages 1 to 2 years to support rapid early growth and brain development, and then at age 2 years transition to low-fat (1%) or non-fat milk to reduce saturated fat and calorie intake. To date, few studies have examined the optimal milk type for children to prevent obesity. This randomized controlled trial will evaluate the effect of consumption of whole versus 1% milk on child adiposity.

Study Overview

• Status: Recruiting
• Conditions: Obesity
• Intervention / Treatment: Behavioral: Introduction of Milk Type; Behavioral: Child Nutrition Counseling

Detailed Description

The prevalence of child obesity in the U.S. has tripled since the 1970s and excess weight gain - even in young children - is a precursor to adult obesity and associated co-morbidities. In the U.S. it is recommended that children consume whole cow's milk (3.5% fat) from ages 1 to 2 years to support rapid early growth and brain development, and then at age 2 years transition to low-fat (1%) or non-fat milk to reduce saturated fat and calorie intake. However, surprisingly few rigorous trials to support recommendations on optimal milk type have been conducted and existing observational studies paradoxically suggest that lower fat milk consumption is associated with increased adiposity in children. The effects of the types of fat found in milk on cardiometabolic disease risk have also been questioned. This randomized controlled trial will evaluate the effect of consumption of whole versus 1% milk on child adiposity and other health and developmental outcomes beginning after toddlers have successfully transitioned from breastmilk and/or formula to cow's milk at 2 years of age. Investigators will recruit 625 parents of toddlers and randomly assign 625 toddlers to either whole or 1% milk groups for 1 year (with estimated final sample size of 500). Our primary aim is to determine how milk fat type (whole versus 1%) consumed from age 2 to 3 years affects change in adiposity as measured by waist-to-height ratio (primary outcome), body mass index, tri-ponderal mass index, and waist circumference. Secondary aims are to evaluate how milk type consumed from age 2 to 3 years affects changes in milk, total and saturated fat, added sugars, and total energy intake and overall diet quality, as well as blood lipids and vitamin D status, and neurocognitive development. Results from the Milk-TOT Study can help pediatric health care providers give evidence-based dietary recommendations to improve child weight and health, and can inform the types of milk provided to participants in the federal nutrition programs which collectively provide milk to over half of all young children in the U.S.

• Study Type: Interventional
• Enrollment (Estimated): 625
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Lorrene Ritchie, PhD; Phone Number: (510) 987-0523; Email: lritchie@ucanr.edu

Study Locations

• United States
  • California
    • Oakland, California, United States, 94607
      • Recruiting
      • Nutrition Policy Institute, University of California Agriculture and Natural Resources
      • Contact: Kassandra Bacon; Phone Number: 510-987-9023; Email: Milktotstudy@ucanr.edu
      • Contact: Ryan Williams; Phone Number: 510-987-9023; Email: Milktotstudy@ucanr.edu
      • Principal Investigator: Lorrene Ritchie, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Parents of children: 1) willing to be randomized to provide either only whole or 1% milk to their child for 1 year, 2) access to a smart phone and a tablet, laptop or computer with internet and email at home, 3) ability to speak and read English or Spanish for the purposes of receiving study communications and completing surveys and dietary assessments (to avoid needing to translate all study materials and have research staff fluent in other languages due to budget limits), 4) not planning to move outside of the San Francisco Bay Area or discontinue being child's primary caregiver for the next year (e.g., foster care, parent separation).

Exclusion Criteria:

Children: 1) <23 months or >48 months old at recruitment; 2) condition or medication that affects growth or daily feeding, or cardiometabolic health such as hypopituitarism, growth hormone deficiency, inborn error of metabolism, syndromic obesity, familial hypercholesterolemia, 3) weight-for-length or height below the 2nd percentile, 4) lactose intolerance, milk allergy or other dietary restrictions (e.g., vegan) that impact ability to consume dairy or otherwise limit dietary intake, 5) resides in more than one household (e.g., shared care by separated parents), and 6) not covered by public or private medical insurance (may reduce well-child doctor visits). If two eligible children are in a household, one will be randomly selected to participate.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Whole Milk; Whole Milk consumption for one year	Behavioral: Introduction of Milk Type; Beginning at approximately age 2, milk (equivalent to 2 cups/day) will be provided at no cost to the family for one year.; Behavioral: Child Nutrition Counseling; Parent/caregivers will receive quarterly phone-based counseling by a Registered Dietitian (RD) on how to introduce the toddler to the assigned milk and the importance of continuing to drink the assigned milk for the one year.
Experimental: 1% Milk; 1% Milk consumption for one year	Behavioral: Introduction of Milk Type; Beginning at approximately age 2, milk (equivalent to 2 cups/day) will be provided at no cost to the family for one year.; Behavioral: Child Nutrition Counseling; Parent/caregivers will receive quarterly phone-based counseling by a Registered Dietitian (RD) on how to introduce the toddler to the assigned milk and the importance of continuing to drink the assigned milk for the one year.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in waist-to-height ratio	Waist-to-height ratios will be calculated using measured height in m and waist circumference in m.	Baseline and 12-months after the start of the study.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in waist circumference z-score	Waist circumference z-scores will be determined using measured waist circumference and CDC growth curves.	Baseline and 12-months after the start of the study.
Change in dietary intake	Energy (kcals/day), milk (cups/day and %kcals), total dairy (cups/day and %kcals), total fat (g/day and %kcals), saturated fat (g/day and %kcals), added sugars (g/day and %kcals) and calcium (mg/day) intake will be measured using 24-hour recalls.	Baseline and 12-months after the start of the study.
Change in diet quality	Diet quality will be measured using the healthy eating index-2020 from 24-hour recalls.	Baseline and 12-months after the start of the study.
Change in blood measures	Lipid concentrations, glucoregulatory indices, and 25(OH)D concentrations will be measured in a morning blood draw.	Baseline and 12-months after the start of the study.
Change in brain growth	Head circumference z-scores will be determined using measured head circumference in cm and CDC growth curves.	Baseline and 12-months after the start of the study.
Change in neurocognitive development	Cognitive, communication and physical development scores will be determined using the Developmental Assessment of Young Children-2 tool.	Baseline and 12-months after the start of the study.
Change in body mass index z-score	BMI z-scores will be determined using measured height in m and weight in kg to calculate kg/m^2, and Centers for Disease Control and Prevention (CDC) growth curves.	Baseline and 12-months after the start of the study.
Change in tri-ponderal mass index	Try-ponderal mass index (TMI) will be determined using measured height in m and weight in kg to calculate kg/m^3.	Baseline and 12-months after the start of the study.

Collaborators and Investigators

• Sponsor: University of California, Davis
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); Stanford University
• Investigators: Principal Investigator: Lorrene Ritchie, PhD, Nutrition Policy Institute

Study record dates

Study Major Dates

• Study Start (Actual): August 15, 2024
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): June 30, 2028

Study Registration Dates

• First Submitted: December 11, 2023
• First Submitted That Met QC Criteria: January 19, 2024
• First Posted (Actual): January 30, 2024

Study Record Updates

• Last Update Posted (Actual): May 18, 2026
• Last Update Submitted That Met QC Criteria: May 13, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: 1757040; R01DK131217 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No