Our Gemara on amud beis relates medical advice from the great Amora and physician Shmuel, and one of the practices that he considers to be in the top three of irreparable bodily harm is to “Eat bread and not walk four cubits afterward.” Rashi adds that this warning is in regard to going to sleep right after eating without walking a bit. There are some technical contradictions between Shmuel’s advice and the Rambam’s medical advice (Deos 4:2) which the commentaries deal with, however taken as a whole, the implications of these teachings are that sedentary behavior is deleterious to one’s health.

 

It is not for nothing that some health experts are calling sitting, the “new smoking.” Is it that harmful? According to Vallance et. al (American Journal of Public Health. 2018 November; 108(11): 1478–1482, “Evaluating the Evidence on Sitting, Smoking, and Health: Is Sitting Really the New Smoking?”), while sitting is not truly as bad as smoking, it is seriously detrimental:

 

“Excessive sitting time almost doubles the risk of type 2 diabetes, but only increases incidence and mortality risk associated with other common chronic diseases by approximately 10% to 20%. In terms of absolute risk difference, these relative risk (RR) estimates correspond to an excess of around 33 Cardio-Vascular related deaths, 27 cancer-related deaths, and 610 incident cases of diabetes per 100 000 persons per year in people with the highest volumes of sitting compared with those with the lowest volumes of sitting. Sitting has also been found to be adversely associated with the risk of depression and physical health-related quality of life domains.” 

 

We might rationalize that what we do with our bodies is a personal choice and not a moral matter. However, the Rambam (Deos 3:3 and 4:1) exhorts: 

 

“It is impossible to understand and become knowledgeable in the wisdoms when one is starving or sick, or when one of his limbs pains him…Since maintaining a healthy and sound body is among the ways of God - for one cannot understand or have any knowledge of the Creator, if he is ill - therefore, he must avoid that which harms the body and accustom himself to that which is healthful and helps the body become stronger.”

 

Why do we tend to ignore such mitzvos? Why would some be horrified to choose a lenient hechsher but have no problem eating way beyond what causes clinical obesity?  Of course there is a natural hesitancy to overemphasize physical health as it can lead to narcissistic preening and strutting about. On the other hand, gluttony, aside from the terrible health costs which really are mitzvos-related opportunity costs, it also leads to indolence and arrogance. As it states in Devarim (32:15):

 

וַיִּשְׁמַ֤ן יְשֻׁרוּן֙ וַיִּבְעָ֔ט שָׁמַ֖נְתָּ עָבִ֣יתָ כָּשִׂ֑יתָ וַיִּטֹּשׁ֙ אֱל֣וֹק-ה עָשָׂ֔הוּ וַיְנַבֵּ֖ל צ֥וּר יְשֻׁעָתֽוֹ׃

 

So Jeshurun grew fat and kicked. You grew fat and gross and coarse. They forsook the God who made them And spurned the Rock of their support.

 

We have to be careful and not assume that all heavy girth represents bacchanalia, as one of the most notable ascetic amoraim, Rabbi Yochanan was also unusually corpulent (Berachos 13b). Yet, we know that Rabbi Yochanan was so ascetic that even while in utero, he was able to reverse and quell the cravings he was inducing in his mother, avoiding her having to eat on Yom Kippur (Yoma 82b). Additionally, he miraculously had his eyes covered with drooping eyebrow hair so as not to see forbidden sights (Bava Kamma 117a). Therefore, while for our own [personal standards we must take seriously the obesity epidemic of modern life, we also should not judge or condemn others.  And, this is aside from a quest for extreme thinness that does not have to do with health, but rather represents an insane standard imposed by a crazy culture.