Garudapurana 1.161.6

1.161.6

kṣunnāśo 'rucivatsarvaṃ savidāhañca pacyate /
jīrṇānnaṃ yo na jānāti so 'pathyaṃ sevatenaraḥ //

loss of hunger, and everything is digested with a burning sensation, as if without appetite; / the man who does not know when food is digested indulges in unwholesome food;