This word is acceptable for play in the UK dictionary that is being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. Somebody following a diet, a dieter.

n. One who lives in accordance with prescribed rules for diet; a dieter.

Relating to a dieting or to a dietary.

n. One who adheres to a certain or prescribed diet; one who considers the regulation of a course of food as important for the preservation of health; a dietetist.

"This casual private intercourse with Israel, but served to manifest him in his far lesser lights; thrifty, domestic, dietarian, and, it may be, didactically waggish."

dieter