Mothers will be contacted at 7 (±3) days,1 (±7 days), 2 (±7 days), 3 (±7 days), 6 (±7 days) months after delivery by phone calls by four investigators blinded to randomization. Following a structured interview mothers will be asked whether the infant had been breastfed during the last 24 hours. Mothers will be then asked whether the infant had been fed any water and/or fruit juice and/or formula and/or semi solid and/or solid foods during the last 24 hours.