Русско-английский словарь пословиц и поговорок
ЕШЬ ВВОЛЮ, ПЕЙ В МЕРУ
You can eat as much as you like, but do not indulge in drinking
Cf:Bread at pleasure, drink by measure (Br.). Eat at pleasure; drink by measure (Am.). Eat at pleasure, drink in (with) measure (Am.,Br.)