Abstract
BACKGROUND: Social inequalities in health emerge early in life. The French Malin program, a multi-behavioral and multilevel intervention targeting both individual and structural factors, was co-created by participatory approaches involving diverse stakeholders. These stakeholders include end-users, the French Red Cross, non-profit associations, and two French pediatric societies. The program aims to promote healthy feeding practices (such as breastfeeding) and foster optimal lifestyle behaviors to prevent obesity among children from socially disadvantaged families. The ECAIL study aims to evaluate its effectiveness. METHODS: ECAIL is an ongoing single-blind, two-arm, parallel-group randomized controlled trial, with balanced (1:1) randomization at the individual level. Co-designed with the stakeholders of the Malin program, the trial has been implemented since 2017 in Northern France. Pregnant women are screened for social disadvantages at the main hospital maternity wards in Lille and Valenciennes with the assistance of healthcare providers. Eligible participants are then enrolled for follow-up by trained dietitians, who provide home visits until the child’s second birthday. Participants in the intervention arm receive the two components of the Malin program: (1) personalized support, including the promotion of breastfeeding, advice, and practical tips for a balanced diet and active lifestyle and (2) incentives to access kitchen utensils and healthy foods at reduced prices. Participants in the control arm receive usual care. Primary and secondary outcomes include rate and duration of breastfeeding and complementary feeding practices, dietary intake and lifestyle patterns in children at age 1 and 2 years, and the risk of obesity at age 2. Quantitative data are primarily collected with face-to-face questionnaires and anthropometric measurements. Additionally, semi-structured interviews with study participants and stakeholders will contribute to the process evaluation of this complex intervention. DISCUSSION: The co-creation of ECAIL, utilizing a bottom-up approach with key stakeholders of the existing Malin program, is a meaningful step toward integrating experiential and academic knowledge. By leveraging mixed data, the findings from this action-research are expected to provide critical insights into the intervention: what it entailed, how it worked, for whom, and to what extent. Amid rising food insecurity, this knowledge will be pivotal in refining the Malin program as it scales up. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03003117. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-025-25004-0.