German Registry of 45,569 Children Links Very Low-Carbohydrate Diets to Slower HbA1c Rise and Stable BMI in Type 1 Diabetes

The DPV prospective registry captured carbohydrate intake at least twice yearly in 45,569 youths aged 1-17 years. VLC (<10%), low-carbohydrate (10-25%), and standard (≥26%) groups were followed for means of 2.18, 2.40, and 3.67 years. Mixed-effects models adjusted for age, sex, and diabetes duration showed dose-dependent attenuation of HbA1c rise and smaller BMI z-score increases in lower-carbohydrate groups. No between-group differences emerged in height velocity or rates of severe hypoglycemia and DKA. These observational patterns align with smaller adult and pediatric cohorts but extend duration and sample size substantially.

Prior small interventional studies and the 2018 Lennerz et al. observational series (n=316) reported similar glycemic and insulin-sparing effects yet flagged possible LDL-C elevation. The DPV analysis did not capture lipid trajectories or micronutrient status, leaving open whether metabolic gains persist once puberty and growth velocity change. Confounding by self-selection remains plausible; families electing VLC diets may differ in adherence behaviors or access to technology.

A planned 5-year DPV update will incorporate continuous glucose monitoring metrics and DXA bone density to test whether early glycemic advantages translate into reduced microvascular risk without compromising peak bone mass. An RCT powered for growth and time-in-range endpoints is required before guidelines can shift.