BackgroundA 6-food elimination diet in pediatric eosinophilic esophagitis (EoE) is difficult to implement and may negatively impact quality of life (QoL). Less restrictive elimination diets may balance QoL and efficacy. ObjectiveWe performed a multi-site, randomized comparative efficacy trial of a 1-food (milk) elimination diet (1FED) versus 4-food (milk, egg, wheat, soy) elimination diet (4FED) in pediatric EoE. MethodsPatients aged 6 to 17 years with histologically active and symptomatic EoE were randomized 1:1 to 1FED or 4FED for 12 weeks. Primary endpoint was symptom improvement by Pediatric EoE Symptom Score (PEESSv2.0). Secondary endpoints were proportion achieving histologic remission (<15 eosinophils/high-power field [eos/hpf]); change in histologic features (histology scoring system [HSS]), endoscopic severity (endoscopic reference score [EREFS]), transcriptome (EoE diagnostic panel [EDP]), and QoL scores; and predictors of remission. Results63 patients were randomly assigned to 1FED (n=38) and 4FED (n=25). In 4FED versus 1FED, mean PEESSv2.0 improved -25.0 versus -14.5 (p=0.04) but remission rates (41% versus 44%; p=1.00), HSS (-0.25 versus -0.29; p=0.77), EREFS (-1.10 versus -0.58; p=0.47) and QoL scores were similar between groups. The EoE transcriptome normalized in histologic responders to both diets. Baseline peak eosinophil count predicted remission (OR 0.975, 95% CI 0.953–0.999, p=0.04; cut-off ≤42 eos/hpf). The 4FED withdrawal rate (32%) exceeded 1FED (11%) (p=0.0496). ConclusionsAlthough 4FED moderately improved symptoms compared to 1FED, the histologic, endoscopic, QoL, and transcriptomic outcomes were similar in both groups. 1FED is a reasonable first choice therapy for pediatric EoE given its effects, tolerability, and relative simplicity.