The excuses that legitimately permit abstaining from fasting are those illnesses that prevent the ordinary course of life. If a person is afflicted with a condition such that, were it left untreated, their life would be endangered or their recovery would be significantly prolonged, and if the treatment itself precludes fasting, then in such a case the person may refrain from fasting. However, this determination must be made on the basis of the assessment of a qualified physician or a medical board.
In this context, obesity does not, in and of itself, constitute an absolute excuse for not fasting. On the contrary, fasting may in fact be beneficial for individuals experiencing this condition. Nevertheless, if a course of treatment has been initiated and its proper progression significantly requires the intake of medication or similar interventions during the day, and if the treatment is of a vital and non-deferrable nature, then in that case a legitimate excuse for not fasting may arise. However, the aforementioned considerations must be taken with due seriousness.