Mahabharata 13.130.44

आहारनियमं कृत्वा मुनिर्द्वादशवार्षिकम्मरुं संसाध्य यत्नेन राजा भवति पार्थिवः

āhāraniyamaṃ kṛtvā munirdvādaśavārṣikammaruṃ saṃsādhya yatnena rājā bhavati pārthivaḥ

Our plain-language meaning of this verse is waiting for scholar review.