Faltering Growth (Failure to Thrive)

Faltering growth, now termed faltering weight and historically failure to thrive, refers to weight gain in infancy or childhood that is slower than expected for age and sex. The 2026 AAP and NASPGHAN clinical practice guideline identifies three signs, each defined by z-score cutoffs: a child’s weight for their length or age falls below roughly the 5th percentile, weight gain before age 2 slows to the bottom few percent for age, or a child drops substantially across the growth chart over time. The panel replaced the older term because “failure to thrive” was imprecise and made caregivers feel blamed (Kersten et al., 2026). Faltering growth is not a psychiatric diagnosis and does not appear in DSM-5-TR. It is a multifactorial clinical designation that reflects medical, nutritional, developmental, and social contributors (Meyer, 2024).

In nutritional psychology, faltering growth is a central outcome construct because it marks where dietary intake behaviors (DIBs), caregiver feeding practices, and measured child growth converge. It affects roughly 5% to 10% of young pediatric patients. Clinicians evaluate it through feeding and developmental assessment rather than routine laboratory testing, and they treat feeding interaction, caregiver mental health, and food insecurity as assessable clinical contributors (Kersten et al., 2026). Faltering growth also overlaps diagnostically with ARFID, which counts impaired growth among its criteria, and severe weight faltering in infancy predicts later psychomotor delay and intellectual impairment (Olsen et al., 2023).