Attantapasutta 2.6

2.6

ekāhikampi āhāraṃ āhāreti dvāhikampi āhāraṃ āhāreti …pe… sattāhikampi āhāraṃ āhāreti. Iti evarūpaṃ aḍḍhamāsikampi pariyāyabhattabhojanānuyogamanuyutto viharati.

They eat once a day, once every second day, up to once a week, and so on, even up to once a fortnight. They live pursuing the practice of eating food at set intervals.