Our physical and mental well being depend to a great extent on what we eat, how we eat and how much we eat.
Mitahara is considered as one of the Yamas in ancient Indian text.
Mita means 'moderate'
Ahara means 'diet'
Hatha Yoga Pradipika defines Mitahara as 'agreeable and sweet food, leaving 1/4th of the stomach free and eaten as an offering to Shiva'.......HYP 58
HYP recommends that one should eat only when one feels hungry. Sweet food means fresh, pleasant tasting food not that which has sugar. Offering to Shiva means that the yogi should eat to nourish the body as a vehicle for spiritual evolution.
Yoga doesn't classify food as carbohydrates, proteins and fats. Instead it groups them into Saatvic, Raajsik and Taamsik according to the effect they have on the body and mind.
Taamasic food is one which makes us lethargic or sluggish. Raajsik food is that which brings activity & restlessness. Saattvic food is that which makes us feel light, energetic & enthusiastic.
Further, some foods are 'Apathya' (to be avoided) and some are 'Pathya' (to be consumed).
Unhealthy diet is one which is reheated after becoming cold, which is dry (devoid of natural oil), which is excessively salty or acidic, stale or has too many mixed vegetables .....HYP 1.60
Healthy diet includes grains, wheat, rice, barley, milk, ghee, brown sugar, crystallised sugar (Mishri), honey, dry ginger, cucumber, some veggies, Moong and other pulses, pure water.....HYP 1.62
The most important attribute of a diet is that it should nourish the 7 dhatus: skin, flesh, blood, bone, marrow, fat and semen/ova. Anything that destroys their natural balance should not be consumed.
Not only the right kind of food but also the proper quantity of food at the right time is also important. The right amount of food can be judged by our body. When we listen to our body attentively and eat mindfully we know where to stop. The principle is that Prana should not be wasted in digestion.
Keeping a pleasant & happy state of mind while cooking and eating can help retain the Prana in the food. Bhagwad Gita also induces verses on Mitahara in chapter 6. It states in verse 6.16 that a yogi must neither eat too much nor too little, neither sleeps too much nor too little.
This yogic diet is devoted to yogis who practice sadhna daily. Even for a house holder such a diet will help purify the body and stabilise the mind.