The Compendium of Kāśyapa 8.3.44

8.3.44

sabhaktaṃ bhaktayormadhye grāsagrāsāntare paraḥ
pūrvaṃ bhaktasya bhaiṣajyaṃ na karoti balakṣayam

with a meal, between two meals, with every morsel, and between morsels. / Medicine [taken] before a meal does not cause loss of strength;