While not every talmudic folk remedy is popular today — most Jews aren’t found reciting psalms to heal dog bites — Jewish law does command that we do what we can to keep ourselves healthy.

The central Torah law on health is found in Deuteronomy 4:9 and 4:15, which instruct us to take utmost care and “guard yourself scrupulously.” According to Rabbi Daniel Pressman of Congregation Beth David in Saratoga, this was interpreted in later Jewish law to mean that Jews have an obligation to take care of themselves. “Which starts with not doing anything stupid,” said the Conservative rabbi.

“Don’t take foolish risks, and don’t say, ‘God will protect me from my own carelessness.'”

While doctors have an obligation to heal, the patient has an obligation as well. Jewish law commands the patient to seek healing and live in a healthful environment. As such, Jews are forbidden to live in a place without a doctor, or clean water.

While ideas about health have certainly changed over the generations — smoking was not widely believed to be unhealthy until the late 20th century (in medieval times it was considered an aid to digestion) — the general halachic principle about health has remained clear: The body is given to us by God, and we have an obligation to maintain it.

“My body is like a car on lease,” said Rabbi Judah Dardik of Beth Jacob Congregation in Oakland. “It’s on loan. By fulfilling this mitzvah and taking care of my body, I’m giving myself many more years on this planet.”

Dardik, who goes running several times a week, added that Judaism is a religion that tries to elevate our lives, and therefore gets involved in all the details. “Halachah has something to say about everything,” said the Orthodox rabbi. “I’m not only connecting with God when I’m studying Torah — I’m serving HaShem and developing myself when I go for a run, or when I lie down for a good night’s sleep.”

Rabbi Stephen Pearce, of San Francisco’s Reform Congregation Emanu-El, concurred. “A properly functioning body, one that’s properly rested, can do God’s work.”

The debate in Jewish circles, said Dardik, is “what is going to be the ultimate conclusion to the scientific debate?”

Of course, what’s seen as unhealthy today might have been par for the course in biblical times. Judges 3:17 refers to Eglon, the king of Moav, as obese — but uses the Hebrew word bari, which literally means, healthy. Other references to Eglon make it clear that “bari” in this passage indicates his size.

“It’s not that they were so foolish medically,” said Dardik. “For them, being heavy was indeed a great survival tactic.”

Judaism also includes many dietary laws, some of which may not ring true to the contemporary ear. The Talmud suggests making your food float in water to prevent indigestion, for instance. But having a healthy diet is paramount.

Kashrut has an element of the old “you are what you eat” adage, as well. Scavengers — animals that eat dead animals — are seen as unclean. Certain aggressive animals, like swans or birds of prey, aren’t kosher either.

In a situation where science has shown us that something clearly damages health, such as smoking, Jewish law can adapt to proscribe that behavior.

“There are some interesting responsa banning smoking,” said Rabbi Melanie Aron of Reform Congregation Shir Hadash in Los Gatos. “In yeshivas in Israel, smoking is very common. But there are some rabbis who took the high ground and said it should be banned.”

While Jewish law instructs us to keep ourselves healthy, it also mandates the healing of others. That mandate is probably one of the reasons Jews have always been interested in medicine, according to Pressman. “It’s holy work,” he said.

The Jewish tradition of bikur holim, or visiting the sick, is a religious obligation that exists not just to keep the ill from feeling lonely, but to heal them as well.

“It’s a religious obligation to visit them and care for them,” said Pearce. “The Talmud says, ‘He who visits the sick causes him to live.'”

The saving of a life is such a mitzvah that it overrides any other commandment, including keeping the Sabbath or fasting on Yom Kippur.

“If a doctor says you can’t fast on Yom Kippur, you can’t,” said Pressman. “You’re not just allowed to eat; you’re required to eat.”