The classic ketogenic diet (cKD) requires constant nutritional monitoring over time both to ensure its effectiveness and to reduce the likelihood of short- and long-term adverse effects. We retrospectively described the use of remote monitoring by e-mail during the first year of follow-up on cKD in 34 children (47% males; age range: 2−17 years) diagnosed with drug-resistant epilepsy (DRE; n = 14) or glucose transporter type 1 deficiency syndrome (GLUT1-DS; n = 20). All the e-mails were evaluated analyzing their frequency and content at 3, 6 and 12 months. Three families never sent e-mails. A median of 36.0 (IQR 23.0–64.0) e-mails per family were sent during the 12 follow-up months by the 31 patients. GLUT1-DS patients sent a greater number of e-mails than the DRE group (median 39.0 (IQR 25.5–56.5) vs. median 26.0 (IQR 19.0–65.0)). At the end of the follow-up period, a greater number of e-mails had been exchanged between the nutritional team and the families belonging to the group that increased its linear growth (median 83.5; IQR 48.0–102.0), compared to the other ones. Constant remote monitoring by e-mail could be a feasible and effective way for a better cKD management.