The neshama (soul) can only enter this world in a physical body. The body is the soul's garment to attain its purpose in this world, as well as directly offering an instrument for elevation. Only through and with the body can we carry out the practical mitzvos of the Torah.
Hashem has commanded us to protect and guard our bodies: "Guard yourself and guard your soul very carefully" (Deuteronomy 4:9-10). This commandment is so important that our sages taught it is part of the commandment not to forget the Giving of the Torah:(quoted from Azamra.org)
"Guard yourself and guard your soul very much lest you forget the day when you stood before HaShem Your G-d at Horev" (Deuteronomy 4:9-10). The Kli Yakar explains: "'Guard yourself' means taking care of the body."
"The wise person has his eyes in his head" (Koheles 2:14) -- "He sees what is ahead" (Avot 2:9). Good health is a precious gift, and the wise person does everything necessary to protect it from possible hazards by taking proper care of the body. On the other hand, "The fool looses everything he is given" (Chagiga 4a). Our sages teach us that when a doctor heals the sick, the doctor is performing the mitzva of returning lost property: "And you shall return it to him" (Deuteronomy 22:2) - "This refers to the loss of the person's body, i.e. his health" (Sanhedrin 73a; see Rambam's Commentary on Mishneh Nedarim 4:4).
I’m going to debase myself now, publicly. I have no strange fetish for exposing my personal business, but because someone else did so doing affecting me, perhaps my doing so will make a difference.
I am a foolish man. Though it’s a passive foolishness, it’s foolishness still. For so many mitzvot I work hard, go out of my way, and invest serious effort, money and time. Yet for this mitzvah my actions have been purely passive. And it almost killed me.
My problem is simple. I spend most of my day in front of a computer, as do so many others nowadays. No different than many other sedentary and office jobs, or maybe it is – more concentration, less physical movement, sitting for hours on end. This is my work, as well as many side efforts including this blog. More and more time…sitting.
The result: Over the past 25 years I gained 70 pounds. Being I started as a "solid guy" and am of average height, the effects are...not positive. What does 70 pounds mean with a sedentary lifestyle?
Tired all the time, without energy, irritable, frequently out of breath, hot flashes, poor sleep, difficulty with concentration & memory, receding gums, and constant cramping.
"I don't feel well", "I just can't", "Sorry, I'm not up for it", these have become my constant state of being. In middle age, this is a disaster.
Those feelings don't come without a host of bad medical test results, medical diagnoses and management medications. Yet the situation, meaning my health, has continued to deteriorate...
…to be continued.