Maimonides’ Guide to Healthy Eating: Personalized Nutrition for Body and Soul

What we eat — and how we digest our food, is the primary factor influencing our state of health, according to Maimonides (the Rambam). He even compared harmful food to a deadly poison. Even the elderly and those with a weak constitution can maintain good health through proper nutrition and a healthy lifestyle.

What is a healthy diet? According to the Rambam, healthy nutrition is personalized to a person’s temperament, age, occupation, and health condition. For example, someone who is overweight requires a different diet than someone who is underweight. Likewise, a person engaged in strenuous physical labor needs different nutrition than someone who spends most of the day sitting in an office.

There is a strong similarity between the Rambam’s approach to nutrition and that of traditional Chinese medicine. Both systems maintain that diet should be determined according to a person’s elemental nature (fire, air, water, or earth), based on the theory of bodily humors. In addition, the Chinese medical approach to treating illness closely resembles the Rambam’s therapeutic method.

The basic assumption underlying both Chinese medicine and the Rambam’s medical philosophy is that a healthy soul in a healthy body is essential for quality of life and longevity.

Adapting Diet to Environment and Seasons

The Rambam ruled that a person should adapt to their natural environment. Accordingly, diet should be adjusted based on the seasons and geographic location.

• In winter, it is recommended to eat warming foods and use a small amount of warming spices, such as meat and winter spices.

• In summer, it is preferable to eat foods that cool the body, such as high-quality dairy products only (goat cheese, fermented yogurt), and cooling fruits and vegetables (zucchini, pumpkin, watermelon, and melon).

However, before considering the seasons, one must first assess a person’s temperament. Someone with a cold constitution may need strengthening foods even in summer, because this reflects their underlying condition. For example, a person suffering from urgent diarrhea should be given strengthening foods that remain longer in the stomach: lean, high-quality meat, fish, cooked vegetables, and white (not whole) rice.

According to the Rambam, food itself is medicine, primarily preventive medicine, for many illnesses. In light of this, he divided foods into beneficial and harmful categories — always relative to the individual’s personal condition. From the Rambam we learn that nutritional therapy is inherently personal: what is good for one person may be harmful to another.

It is worth mentioning the words of Rabbi Menachem Mendel Schneerson, the Lubavitcher Rebbe, who said: “Nature has changed, and so have the climate and people, as well as nutrition and the nature of food.”

Foods That Should Never Be Eaten

The Rambam distinguished between foods that are extremely harmful and should never be eaten, and foods that are generally unhealthy but may be eaten occasionally and in small amounts: “There are foods that are extremely harmful, and it is proper that a person never eat them… they are to the body like deadly poison”
(Mishneh Torah, Book of Knowledge, Laws of Character Traits, ch. 4).

Foods that should be avoided entirely:

• Large, old, salted fish (the larger the fish, the more toxins and mercury it contains)

• Old, heavily salted cheese (excess salt is dangerous, and aged cheese may contain harmful bacteria)

• Old, salted meat

• Mushrooms and truffles

• Foods with a foul odor

Foods That Should Be Eaten Only in Small Amounts

“There are foods that are harmful, though not as harmful as the former. Therefore, a person should eat them only sparingly and infrequently, and should not make them a regular part of their diet”
(Mishneh Torah, Book of Knowledge, Laws of Character Traits, ch. 4).

Foods to eat rarely and in moderation:

• Milk and cheese that have stood more than 24 hours after milking

• Meat of large cattle and large goats

• Beans and lentils (today it is known that sprouting improves digestion and makes them healthier)

• Barley bread

• Matzah bread

• Cabbage

• Garlic and onions (in moderation; garlic can be very healthy but also dangerous for people with a “hot” constitution)

• Mustard (not good in summer)

• Radishes (not good in summer)

• Laxative vegetables — people with weak digestion should cook them

• Carobs (cause constipation)

• Citrus fruits (except lemon, grapefruit, pomelo, and sweet grapefruit, which are less acidic)

• Unripe fruit

• Waterfowl and young pigeons

• Fresh (moist) dates (dried dates are good; fresh dates are excellent)

• Bread toasted or kneaded with oil

• Finely sifted semolina

• Large fish

Foods Beneficial to Health

• Whole wheat bread (“spelt” in the Rambam’s terminology): “Flour made from wheat that has not been soaked in water and not peeled”
  (Treatise on Asthma, ch. 3)

• All fruits (especially almonds, nuts, and grapes; citrus fruits are less ideal due to excess phlegm)

• Olive oil (but not on very hot days)

• Poultry, especially chicken soup

• Fish — particularly small fish rich in omega-3; mullet is considered especially beneficial

• Eggs

• Cow’s milk and goat’s milk (today goat’s milk is preferred; only fermented yogurts are recommended for gut health)

• Beef and lamb (for thin and weak individuals only)

• “Honey and wine are harmful for the young but beneficial for the elderly” (Laws of Character Traits, ch. 4)

How to Eat Properly

In addition to identifying beneficial and harmful foods, the Rambam offers several guidelines for how to eat:

1. A person should eat only when hungry, and drink only when thirsty.

2. One should not fill the stomach completely, but leave some space.

3. One should not drink water during the meal, but rather drink a small amount of water diluted with wine before eating.

4. During a meal, lighter foods should be eaten before heavier ones — for example, poultry before red meat, and eggs before poultry or beef.

5. Diet should be adapted to the seasons: in summer, eat cool foods without spices and with vinegar; in winter, eat warm, spiced foods. In summer, one should also reduce food intake to two-thirds of what is eaten in winter.

6. One should eat while seated, not standing. Walking during or immediately after a meal interferes with digestion and endangers health.

7. A person should eat only after relieving themselves and washing.