Hatha Yoga Pradipika, the yogic text tells the concept of yogic diet (mitahara) in chapter 1 – Asana shloka 58
भुज्यते शिव-सम्प्रीत्यै मिताहारः स उच्यते ||
bhujyate śiva-samprītyai mitāhāraḥ sa uchyate ||
Agreeable and sweet food, leaving one fourth of the stomach free, and eaten as an offering to Lord Shiva is Mitahara (मिताहार).
What is Mitahara – the yogic diet
susnighdha-madhur does not literally mean oily and sweet, what it represents here? The food which is fresh, has its juices intact, has pleasant taste and which is not dried is susnighdha and madhur. The diet which is according to one’s metabolism and body type.
chaturthāṃśa-vivarjitaḥ means keep the stomach 1/4 empty. It clearly signifies one should not overload the stomach. It is said it should be half filled with food, 1/4 filled with water and 1/4 with air. Keeping stomach little empty is like giving space to food for churning properly.
bhujyate śiva-samprītyai means eat as an offering to please Shiva (Lord Shiva is is adiyogi, the master of all yogis). Offer the food to God first and eat it as the prasad (the food given by god). Body is temple and God or Lord Shiva resides there. Be in this state- that food is an offering to God residing in the body temple. Why so? The reason is we always offer good and appropriate things to those we love. Be in that state, offer moderate, right, sattvic and delicious food and as a result of prasad this body and mind will be strengthened, purified and get good health.