Jupiter is a very significant planet in Vedic astrology because it bestows prosperity, a strong voice, spiritual enlightenment, cultural sophistication, a liberal outlook, and a generous spirit on its subjects. This is a positive facet of Jupiter, one of its various manifestations. If it’s not placed well in a horoscope, it might also cause you to be overconfident, haughty, and overweight. Depending on Jupiter’s placement in the natal chart and its conjunctions with other planets, it can either make you a generous person or a person without morals.

Because Jupiter is the god of plenty, being overweight might make an already overindulgent person much more so.

In Medical Astrology, Jupiter is the significator of fat, so if it has its effect on the Ascendant or Ascendant lord, and especially if the Ascendant is of the water or Fixed rising sign, then the person gains weight very quickly.
This is an optimistic planet and also generous if it is well placed in the horoscope.

 

For more detail Jupiter not only makes you a good sportsperson but also it will make’s you fat

In medical terminology, Jupiter is the significator of liver, kidneys, lungs and ears, diabetes etc,whenever placement or conjunction with 6th and 8th lord and the running dasha not favourable the native may suffer from above given diseases.