People say that some of Rambam's laws on health are inaccurate in today's era, because of the body change throughout the generations, and that today some foods are good while they used to be bad and vise versa. I'd like to know if anybody knows which laws are relevant today and should be obeyed, and which ones are irrelevant today and can be ignored.

  • 4
    I'd wager your local doctor knows
    – Double AA
    Dec 31, 2021 at 19:35
  • 1
    I actually know someone who follows his diet religiously
    – Chatzkel
    Dec 31, 2021 at 20:28
  • @Chatzkel what religion is that? Clearly can't be Judaism
    – Double AA
    Dec 31, 2021 at 20:58
  • I would suggest that you take a look at the sefer published by Feldheim called The Life-Transforming Diet - feldheim.com/authors/david-j-zulberg/the-life-transforming-diet by David J Zulberg
    – Dov
    Jan 1, 2022 at 17:32
  • 1
    The Rambam would be the first to tell you to rely on the best information available in your time.
    – N.T.
    Jan 2, 2022 at 2:19

2 Answers 2


Following on from my comment above, the Mishpacha ran a piece here, which relates how the timeless tips of Rambam are equally relevant today.

The article brings many points made by the Rambam and notes several adherents of his, all published authors, with testimonials from those who embraced the diet and saw a great deal of success

The main relevant excerpt reads as follows:

Rambam Revival

When South African-born David Zulberg was learning in a Jerusalem kollel, he considered his health condition pretty typical: 30 pounds overweight, sluggish-feeling, and living with a bad case of acid reflux. His doctor urged him to make lifestyle changes, but who had the motivation for that?

And then he chanced upon some information that would eventually change his life — that the Rambam had a lot to say about health. A mild curiosity evolved into a seven-year megaproject that involved tracking down and studying the translations of all ten of the Rambam’s medical works, and then creating a user-friendly diet approach based on those principles that has helped thousands lose weight and keep it off.

Zulberg, today a popular media personality and certified health coach and fitness specialist, wrote three books on health (The Life Transforming Diet, The 5 Skinny Habits, and The Mind Body Synergy Diet) and designed his food plan around the three main health principles of the Rambam: food quantity, exercise, and food quality, in that order.

Regarding portion size: “Overeating is like poison to the body and it is the main cause of all illness… One should not eat until his stomach is full. Rather, [he should stop when] he is close to three-quarters satiated” (Rambam, Mishnah Torah, Hilchos Deios).

The Rambam says that overeating puts a strain on the digestive system that with time will lead to various illnesses. Based on recent studies, the Mayo Clinic, American Obesity Association, and American Diabetes Association have all urged reducing food quantity for improved health.

Regarding exercise: “Without exercise, a good diet alone is not sufficient, and eventually medical treatment will be needed” (Rambam, Medical Aphorisms). “Exercise repels the damage done by most of man’s bad habits” (Rambam, Regimen of Health).

The Rambam defines exercise as physical activity that raises the rate of respiration. The best time to exercise, he says, is at the beginning of the day, before a person eats; exercising after a meal impairs digestion and can lead to illness.

Regarding food quality: “Most illnesses are caused by unhealthy foods” (Rambam, Hilchos Deios).

Remarkably, the most current knowledge of various foods’ effects on health, brought to light in recent years, was spelled out by the Rambam during the Middle Ages. For example, writes the Rambam, “Foods to be limited include flour that has been sifted until no bran remains (white flour). Fatty food should be avoided… it cleaves to the organs. The best type of cheese is that which is made from milk whose fat has been removed. Of the different types of meat, one should choose fowl… other harmful products include fried pastries….”

To reduce food quantity, and in line with the Rambam’s belief that a person should only eat two main meals a day, one meal a day on the Life Transforming Diet consists of either just fruit, or just vegetables (this wouldn’t count as a meal according to the Rambam, but gives one a way to eat the three “meals” a day to which our society is accustomed).

The Rambam suggests eating a single dish at a meal. Digesting various foods at the same time, he maintains, has a deleterious effect on digestion and can lead to illness (there are conflicting viewpoints on this point among nutritionists today). In addition, every food eaten stimulates the appetite separately. When only a single food is eaten, according to the Rambam, the appetite is satiated earlier, and this will prevent overeating. Indeed, multiple published studies have substantiated the Rambam’s claim, showing that food consumption increases when there is more variety at a meal, and that increased food variety is associated with increased body weight. One such study published in Health Psychology in 2008 showed that children presented with a variety of foods at a meal ate 42 percent more than those presented with a single food.

Because of this, one of the two main meals a day on Zulberg’s plan is either primarily protein, or primarily carbohydrate, but the two are generally not combined. Vegetables can be eaten with either choice. The third meal of the day can include both starch and protein. Eating this way, according to Zulberg, will naturally reduce a person’s appetite, resulting in automatic weight loss.

But food is only half the equation — the other half is exercise. According to Zulberg, cardiovascular and strengthening exercises should be done five times a week. He believes that those who follow his plan will benefit from the Rambam’s wisdom and gain the benefits of better health and a more energetic constitution.

The Rambam, who lived from 1135 to 1204, was not only one of the greatest Torah scholars in Jewish history, but was also known as the greatest medical expert of his time. While living in Egypt, he had a thriving private practice to which people flocked from great distances. By age 39, he served as royal physician in the court of Sultan Saladin, famed Muslim military leader who fought the Crusaders and later became ruler of Egypt. The Rambam authored ten major medical works in Arabic, which combined his extensive knowledge of the ancient works of Greek physicians such as Hippocrates and Galen with the most current medical knowledge of his own time. An extensive amount of the Rambam’s medical advice proves to be remarkably current, some even at the vanguard of health conversation today (for example, the Rambam suggests eating only free-range cattle).

In addition to his medical tomes, some of the Rambam’s halachic works, such as Hilchos Deios in the Mishnah Torah, are laden with medical directives, although that doesn’t necessarily give them halachic weight. “The Maharshal in Chullin says that it’s assur to cite medical advice from the Gemara, lest it not work and will besmirch the good names of those quoted,” says Rabbi Moshe Plutchok, rav of Congregation Shaarei Torah in Manhattan Beach, Brooklyn, an eminent talmid chacham with a broad base of historical knowledge. “The Rambam heeded this, and never quoted from the Talmud in his medical works. The general consensus among poskim is that these medical directives are not halachically binding.”

Still, the main health principles of the Rambam are substantiated with current research and are universally agreed upon today, says Zulberg.

The article also notes the impact of Rabbi Yechezkel Ishayek, a close talmid of Rav Shach, and his book To Your Health - The Torah Way to a Healthy Life in Modern Times which is largely based on the Rambam's diet and has since been translated into 6 languages and has sold in excess of 150,000 copies a sure sign that the Rambam's outlook towards food is as relevant as ever.

  • 1
    Good answer. I commented above that I'm not sure we can call it "health principles of the Rambam". After all, he studies ancient Greek and Arab philosophers and copied everything they said. I couldn't find any Jewish traditions in his medical training.
    – Al Berko
    Jan 1, 2022 at 20:16

According to Segal, I., & Blazer, S. (2020) (1), the following can be said

His recommendations demonstrated a fundamental understanding of the human body based on the cumulative knowledge of medical science dating back to Hippocrates, Aristotle, and Galen (~460/384 BC, and 129 AD). This must be taken into consideration when considering the recommendations of Maimonides. For example, there was no refrigeration or pasteurization, and the cause of most diseases was unknown. Despite this, what is most interesting is that many of his recommendations remain true today. This is remarkable given the available knowledge and customs of his time.


The fact that most of Maimonides’ nutritional recommendations are basically accepted by some of the major authorities worldwide is remarkable. Maimonides based his recommendations on astute observation of his patients throughout decades of medical practice. The only total disagreement between the modern recommendations and Maimonides relates to the consumption of fresh fruits, vegetables, and legumes. Hence it is important to understand his rationale for these recommendations (Segal, I., & Blazer, S., 2020).

See table 1 for agreements between the Rambam's recommendations and the contemporary recommendations.

Similary, the Rambam (Shemonah Perakim 3:2) writes:

Likewise, just as when people, unacquainted with the science of medicine, realize that they are sick, and consult a physician, who tells them what they must do, forbidding them to partake of that which they imagine beneficial, and prescribing for them things which are unpleasant and bitter, in order that their bodies may become healthy.

The end-goal of all the advices the Rambam gives, especially in his Hilchot De'ot, but also in Shemonah Perakim, is in order to preserve of bodily health (Shemonah Perakim 5:2)

Reference list

  1. Segal, I., & Blazer, S. (2020). The Maimonides Model for a Regimen of Health: A Comparison with the Contemporary Scenario. Rambam Maimonides medical journal, 11(4), e0029. https://doi.org/10.5041/RMMJ.10396

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