A rabbi I've learned under recently developed some health problems. Fortunately he was diagnosed and treated aggressively, averting some potentially catastrophic problems. Unfortunately, this event was no surprise given his lifestyle, one which is all too common in Western society.
Another rabbi I learned under passed away suddenly a year ago (his 1st yahrzeit is next week, as a matter of fact). He was a wonderful man, a scholar and full of kindness and compassion but he also enjoyed eating and smoking which, in the end, did his heart in. May his soul rest in peace.
It's quite obvious that Western society is getting fatter. Take a trip to your local mall and spend a moment looking around. Other than anorexic teenage girls, most people trundling through on the way to the stores are overweight to one degree or more. And in the Jewish community, this epidemic of obesity is all too prevalent as well. Rav Yonasan Rosenblum, in a column for Mishpachah Magazine, noted that amongst religious Jews, there is an almost cavalier dismissal of the benefits of a healthy lifestyle. To quote:
I once asked a member of a large charedi community, "Why is everybody here so fat?" My friend, an incisive wit, neatly captured the mindset, "The goy says its not good to be fat. What does the goy know?"
Is there any obligation in Judaism to keep one's body in good shape? There is no verse in the Torah demanding exercise on a daily basis or healthy eating, per se. Because of this, people who will make sure to check their tzitzis down to the last fibre each morning will ignore the need to care for their physical selves. I've even heard people justify smoking as the Torah never said it was forbidden. Never mind that tobacco hadn't been discovered by European and Asian society at that time!
And yes, there are great sages like the Rambam who advocated for healthy eating and drinking but these rulings aren't taken with the same gravity as those, for exampe, dealing with the quality of one's lulav and esrog.
There is some verses in the Torah, however, that I believe could be seen as a demand to keep oneself in good shape. Dr. Fred Rosner, in The Medical Legacy of Moses Maimonides, brings the following:
"And he said: If thou sahtl diligently hearken to the voice of the Lord thy God, and wilt do that which is right in His eyes and will give ear to His commandments and keep all His statutes, I will put none of the disease upon thee which I have put on the Egyptians for I am the Lord that healeth thee." (Shmos 15:26)
According to Dr. Rosner, the Torah here emphasizes preventative health care. In other verses, we learn that there is an obligation to go to the doctor if one is sick and needs healing. But this verse implies that a Torah-true lifestyle is all one needs to hold back illness. But where does the Torah hint at caring for oneself physically as part of this Torah-true lifestyle?
There is a common misconception, spread by the doctrine of a major world religion, that the First Man's punishment for listening to his wife was to be cursed. Rav S.R. Hirsch, in his commentary to Bereshis 3:17 notes that the Torah clearly states that "cursed is the ground for thy sake". Having been turfed out of Gan Eden, Adam isn't cursed but must work against natural adversity in order to return to his previously level of perfection. Instead of being at the top, he must climb back there slowly using the resources of the natural world. And then comes this verse:
"In the sweat of thy face shalt thou eat bread." (Bereshis 3:19).
Now, if it is true that Adam isn't cursed, then this statement is not a curse either but merely a statement of the new order. In order to eat, Adam must work physically. Amongst the many ways this can be interpreted is the thought that in order to merit taking in calories, one must consume them as well. Diet and exercise are commanded by God as being the ideal lifestyle.
And anyone with even a rudimentary knowledge of human physiology cannot argue with this idea. There is no doubt in the scientific literature that moderate levels of physical activity, either through labour or exercise, are essential for maintaining health and prolonging life. The evidence for healthy eating is irrefutable. Only someone with blinkers on could possibly argue these points.
What's more, Torah-observant Jews need to be aware that caring for our bodies is as important as caring for our souls as both are a gift to us from God which require the best care to upkeep. We are obsessed with the idea of ever-increasing stringencies in terms of kashrus lest some impure morsel of food taint our souls but the idea of being just as stringent with our bodies and ingesting only foods which are just as healthy in a physical sense as a spiritual one is never considered.
Consider the words of the Rambam in Hilchos Deos:
Since, when the body is health and sound, one treads in the ways of the Lord, it being impossible to understand or known anything of the knowledge of the Creator when one is sick, it is obligatory upon man to avoid things which are detrimental to the body and to acclimatize himself to things which heal and fortify it.
He then goes on to discuss proper measures of eating, including avoiding gorging oneself, limiting caloric intake to periods of hunger, and when to relieve oneself. More importantly, he notes:
A person should not eat until he has walked prior to the meal so that his body begins to become warmed, or he should perform a physical task or tire himself by some other form of exertion. The rule in this matter is that one should exert one's body and fatigue it every day in the morning until one's body beings to warm."
By putting these rules into his Mishneh Torah, a work on halacha, Rambam shows that there is no difference betweeen caring for one's soul and one's body in the service of God. It is incumbent on all Toah-obsevant Jews to eat healthy foods and exercise regularly for this is part of the service of God. May we all be preserved from disease and live our lives in comfort and health.