903. Three Meals on Shabbos

Shabbos 30:8

A wealthy person whose weekday meals are as extravagant as Shabbos meals must also have different foods on Shabbos. If this is not possible, he should change the time of his meals, either making early meals later or late meals earlier.

Shabbos 30:9

One is obligated to eat three meals on Shabbos: evening, morning and afternoon. One should be very careful not to eat fewer than these three meal. Even a needy person who relies on charity should eat three meals on Shabbos. However, if a person is sick from overeating or fasts regularly, then he need not eat three meals. All three must be set meals: wine must be served and one must break bread on two whole loaves. These rules also apply to holidays.