Approximately 6·5 million US children live in food-insecure households, meaning that they have restrained access to the types and amounts of foods they usually eat. The nutrient demands of growth and general sub-par dietary intake of US children by age highlight the importance and difficulty of attaining recommended amounts of critical dietary components to promote health and prevent disease. Evaluation of the evidence for a relationship of food insecurity with key dietary outcomes for the specific stages of child growth at 1–5 years, 6–11 years and 12–19 years has not been previously documented. Bradford Hill criteria of strength, consistency and dose–response were applied to aid evaluation. A comprehensive search of original research on US children using food-security assessment measures indexed to January 2017 was completed and identified sixteen studies that evaluated the relationship of food insecurity with key dietary outcomes. Evidence for a strong, consistent and dose–response relationship of food insecurity with lower vegetable intake compared with food security was determined among children aged 1–5 years and strong and consistent evidence of higher added sugar intake among food-insecure children aged 6–11 years compared with food-secure children was apparent. Adolescent-focused evidence was sparse but revealed adolescence as the paediatric age stage where food insecurity has the most potential for negative impact on child dietary intake. A discussion of future research opportunities includes strengthening the evidence through longitudinal study designs, inclusion of additional nutrients of concern, and stronger mitigation of bias and error.