who begins the practise of yoga without controlling the diet does not make progress in yoga”.The food we eat should be pure(sattvic), untainted(nirmala), and acquired through righteousness and taking as much food as we need to maintain our body.
Ghee is ideal for the yogi on many levels, as a food, mental tonic, and to aid pranayama and Yogic detoxification techniques. It acts on all three bodies perceived by Yoga Philosophy: the physical body, made up of food, through nourishment, increasing digstive fire (agni) and protecting; the astral body, made up of the vital, mental and intellectual sheaves, through purifying intellect; and through its effect of increasing psychic heat, it also acts subtly on the causal body made up of the bliss sheath. However, ghee and milk should only be consumed in moderation as both have the potential to aggravate kapha. Even the most pure foods are dulling (tamasic) if taken in excess.