Cholelithiasis means gallstones. Most gallstones cause no symptoms.

After a heavy meal, especially a fatty meal, the hormone cholecystokinin makes the gallbladder contract to release bile. If a gallstone transiently blocks the cystic duct during this contraction, it causes biliary colic:

This meal relationship occurs because the meal triggers gallbladder contraction, not because fatty food itself creates the stone or necessarily causes cholecystitis. A heavy meal of any type can precipitate an attack. Yamada's Textbook of Gastroenterology, 7th ed., p. 1980. The NIDDK gallstone overview similarly notes that attacks often follow heavy meals.

Cholecystitis is inflammation of the gallbladder, usually when a stone remains impacted in the cystic duct. It may start after a meal like biliary colic, but differs because pain becomes persistent and more severe, typically lasting over 6 hours, with tenderness in the right upper abdomen, nausea/vomiting, and sometimes fever or raised white-cell count. It needs urgent medical assessment. Acute calculous cholecystitis is a complication of symptomatic gallstones caused by cystic-duct obstruction. Fischer's Mastery of Surgery, 8th ed., pp. 2696-2702.