There is a persistent myth that children should begin fasting on the three fasts before their bar/bat mitzvah, no earlier and no later. However, there does not appear to be any precedent for this practice. So when (and how) should children begin fasting?

Although children are not obligated to perform mitzvahs before attaining bar or bat mitzvah, we are obligated to start educating them about the mitzvahs earlier on. When to begin this education (chinuch) varies for different mitzvahs. For example, we may begin teaching children how to light Shabbat candles or don tzitzit around the age of three (or younger). How about fasting?

Before any discussion about the recommended guidelines for fasting, it’s important to note that not all children have the capacity to fast, and, of course, if there is any danger to the child’s health, he or she should not be fasting (this applies to adults as well).

Let’s start with the strictest fast, Yom Kippur, which is mandated in the Torah (the Five Books of Moses).

Before Nine: No Fasting

Before the age of nine, children are not required to afflict themselves by not eating on Yom Kippur. Even if children want to fast, we discourage them lest they endanger themselves.1

(There are some who hold that, nowadays, if children independently wish to fast for a few hours, the custom is that they may do so if they are physically able.2)

Nine or Ten: Progessive Practice

A healthy child should begin to practice fasting at age 9, and a weaker child should begin at 10.3 There is a rabbinic obligation to train these children to gradually increase their fasting time. At first, they should eat their breakfast an hour later than usual, then more, building up toward fasting a whole day.4

Eleven and Twelve: Fasting

According to some, once boys and girls5 reach eleven years of age, they should be trained to complete the entire fast on Yom Kippur. Others, however, hold that they, too, should only fast for a few hours, not the entire fast.6

Primacy is given to the first (stricter) opinion. However, in the case of weak children, we can rely on the second approach, and they need not complete their fast. As a rule of thumb, people are generally considered less hardy than they once were, and it is therefore the custom to not be particular that children who are pre-bar/bat mitzvah complete their fast (unless it is known that the child is healthy and strong enough to fast the entire Yom Kippur).7

The Four Minor Fasts

Strictly speaking, according to many, even older kids need not fast at all during the four minor fasts (Tzom Gedalyah, 10 Tevet, Taanit Esther, 17 Tammuz,) as well as the fast of the 9th of Av.8 Nevertheless, some have the custom to encourage them to fast a bit if they are strong and healthy. This holds true especially for the 9th of Av, which is generally stricter than the other four fasts.9

Sweets and Treats

Although a child is encouraged to eat on a fast day, we nevertheless try to minimize giving sweets and other treats to children who are old enough to somewhat understand the seriousness of these days of mourning.10

May we merit that all of these fast days be transformed into days of joy and happiness!