Does Judaism say if you are fat you should have a diet?

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  • I always thought halacha tells you to take the best care of your body that you can, but never goes into specifics, given that medical authorities can and do change their minds and halacha must not follow them like a puppy. Is this not correct? Mar 30, 2021 at 17:21
  • 1
    It would be proper to clarify this question. Since being fat in itself is not a very descriptive term, perhaps, in the pertinent fields which would help in addressing a halachic conclusion in this topic.
    – Dr. Shmuel
    Mar 30, 2021 at 17:26
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    What does "have a diet" mean?
    – Double AA
    Apr 5, 2021 at 20:03

2 Answers 2


It is a scientific fact that "people who have obesity, compared to those with a normal or healthy weight, are at increased risk for many serious diseases and health conditions" (quote from the US Center for Disease Control, see the full list of serious diseases caused by overweigh here).

So let's see what Judaism teaches us about protecting one's health which includes dieting if one is overweigh.

The rabbinical interpretation of the Torah verse in Devarim 4:15 is that we have an obligation to take care of oneself

וְנִשְׁמַרְתֶּ֥ם מְאֹ֖ד לְנַפְשֹׁתֵיכֶ֑ם
You should guard yourselves very well

The Kitzur Shulchan Aruch (32:1) learns from this that

Because the maintenance of a complete and healthy body is a G-dly path—since it is impossible to understand or apprehend any knowledge of the Creator when one is sick—therefore you must keep away from things that damage the body, and develop habits that improve the body and heal it. Similarly, it is said: “You shall guard yourselves very well.”

(see also SA CM 427:8)

The Rambam (in MT Hilchot Deot chapter 4) develops a number of food-related rules that suggest indeed that overeating is against the laws of the Torah, and that an overweight person should reduce his weight, e.g.,

  • Overeating is like poison to anyone's body. It is the main source of all illness. Most illnesses which afflict a man are caused by harmful foods or by his filling his belly and overeating, even of healthful foods. This was implied by Solomon in his wisdom: "Whoever guards his mouth and his tongue, guards his soul from distress" (Proverbs 21:23); i.e., "guards his mouth" from eating harmful food or eating his fill and "his tongue" from speaking [about things] other than his needs.
  • A person should never eat unless he is hungry, nor drink unless thirsty
  • One should not eat until his stomach is full. Rather, [he should stop when] he has eaten to close to three quarter's of full satisfaction.
  • The rule is that he should engage his body and exert himself in a sweat-producing task each morning.
  • [Conversely,] whoever is idle and does not exercise, or does not move his bowels when he has the need, or is constipated, even if he eats the proper foods and takes care to follow the rules of medicine, will be full of pain for all his days and his strength will fade away.
  • +1 but please correct 1. "The Torah says we have an obligation to take care of oneself" - this is rabbinic speculation, the verse says to distance oneself from idolatry. 2. Rambam did not base his Hilch Deos on Jewish sources, on the opposite, no (fat) rabbis in the Talmud followed Rambam's rulings.
    – Al Berko
    Mar 30, 2021 at 21:30
  • Your CDC quotation merely says that overweightness goes with a higher risk of disease, without saying it causes that risk. Maybe reducing weight won't help, in which case this answer is all moot.
    – msh210
    Apr 1, 2021 at 5:09
  • @msh210 there is no certainty in medicine, everything is about risk and probabilities. If one has an obligation to guard one's health, it means reducing disease risk
    – mbloch
    Apr 1, 2021 at 5:27
  • My point was that reducing weight may be completely irrelevant (according to that CDC quotation, anyway).
    – msh210
    Apr 1, 2021 at 5:29
  • I agree with that claim, I disagree to call interpretations "the Torah". One might use "Rabbis inferred" or "Rabbis understood", or even "Rabbi has had a tradition of Oral Torah", but still this is not what is written in the plain text. Maybe I'm too sensitive to this issue, but in a respected discussion, I prefer to differentiate between the two.
    – Al Berko
    Apr 1, 2021 at 10:12

Although mbloch is right that keeping healthy is an important idea in Judaism, it does not seem that one should start diets (in the usual sense) or even give attention to one's excess fat when overweight. Eating לשם שמים and not for one's enjoyment is a fundament principle in Judaism and according to some part of the Positive Commandment קדושים תהיו. As seen in the second letter below, the emphasis is more on why one eats than what he is eating.

See below for the novel approach of the Lubavitcher Rebbe on dieting:

לכתבו על דבר ששוקל יותר מדי ודאגתו על דבר זה וגם על זה שקשה לו למעט באכילה ושתיה - לדעתי 1) מגזימים הרופאים בהערכתם ההיזק שע"י דיקייט (תוס' משקל) של האדם, 2) היסח הדעת – על כל פנים שלילת התבוננות תמידית בזה – תקל ההתאפקות מאכילה ושתיה יתרום – על־כל־פנים, תחזק מנוחת הנפש ובמילא גם המעטאַבאָליזם (=חילוף החומרים) דהאדם למעט בהשומן שיתר מהמידה, ועוד וגם זה עיקר – שיעבוד השם בשמחה.

אזכיר עוה"פ עה"צ. להודיעו תוכן המצו"ב

(מכתב אדר"ח אייר ה'תשל"ט)

(Free translation)

The Rebbe is writing to someone who is worried about being overweight and is having difficulty reducing his eating and drinking.

The Rebbe replies:

  1. the doctors exaggerate in their assessment of the damage caused by extra weight.
  2. hesach hadas (purposeful distraction) -- at least not constant consideration in this matter - will strengthen the peace of mind and also the metabolism which will help with the excess fat.
    ** The main thing: serve hashem happily.**

The Rebbe writes in another letter about dieting:

Regarding the types of food that should make up your diet:

The types of foods you eat (as long as they are properly kosher) are not as important as the reason why you are eating. Do not eat in order to indulge in pleasure, but eat merely to sate your hunger and to be healthy, thereby enabling you to do good things, etc. See also Shulchan Aruch, Orach Chayim, ch. 231.1

Shulchan Aruch, Orach Chayim, ch. 231.1

Anything that is pleasant for him in this world, his intent should not be for his pleasure, but rather for the service of the Creator, may He be blessed; as it is written (Proverbs 3:6), "In all of your ways, know Him." And the Sages said, "Let all of your actions be for the sake of Heaven." As even optional things – such as eating, drinking...should be for the service of your Creator or for something that enables serving Him. For even if one was thirsty or hungry – if he ate or drank for his pleasure, it is not praiseworthy. Rather he should intend to eat and drink for his sustenance, to serve his Creator.

The Lubavitcher Rebbe does not need corroboration to support his idea. However, חכמה בגויים תאמין recently there have been more doctors agreeing with this approach see this article.

"The phenomenon that weight regain eventually follows intentional weight loss is as certain as smoking causing cancer."

  • Comments are not for extended discussion; this conversation about the correctness of this advice has been moved to chat.
    – Isaac Moses
    Apr 5, 2021 at 19:45

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