Ayurveda suggests that regularly under-eating aggravates vata dosha, while over-eating aggravates all three doshas; vata, pitta and kapha. Here is an excerpt from Charaka Samhita, written several thousand years B.C.
Improper quantity of food is of two types: deficient in quantity and excessive in quantity
Food deficient in quantity will produce the following symptoms :
1. impairment of strength, complexion and plumpness
2. distension and misperistalsis in the abdomen
3. impairement of longevity, virility and ojas
4. affliction of body, mind, intellect and senses
5. impairement of the excellence of dhatus (tissues)
6. manifestation of inauspicious conditions and
7. causation of the eighty varieties of vatika diseases
Food taken in excessive quantity aggravates all the three doshas. One who fills up his stomach with solid food and then takes liquid food in excessive quantity all the three dosas, viz. vata (samana vayu), pitta and kapha residing in the stomach become too compressed and simultaneously aggravated.
These aggravated doshas affect the digested food and get mixed up with it. Then they obstruct a part of the stomach and instantaneously move through upward and downward tracts separately to produce the following diseases in the individual who is taking food in excess :
Vata produces colic pain, constipation, malaise, dryness of mouth, fainting, giddiness, irregularity in the power of digestion, rigidity of sides, back and waist, and contraction and hardening of vessels.
Pitta causes fever, diarrhea, internal burning sensation, thirst, intoxication, giddiness and delirium.
Kapha causes vomiting, anorexia, indigestion, cold fever, laziness and heaviness in the body.