Sir Isaac Newton and Judaism
8 min read
GOOD MORNING! Over the last several months I’ve had multiple readers email me about discussing the importance of healthy eating and regular exercise as part of one’s daily regimen.
A rabbi being overweight is practically a cliché; individuals who are highly disciplined when it coming to religious life often overindulge in areas that are technically permitted by the Torah – such as food. As we shall see, both modern psychology and classical Jewish and rabbinic sources recognize and address this dichotomy.
It has been said that the scope of a rabbi’s synagogue and communal obligations – attending functions like award dinners, weddings, Bar/Bat Mitzvas, circumcisions, and visiting shiva homes when someone passes – can seem more like a tasting tour than typical communal responsibilities. So yes, the opportunities for overindulgent behavior seems to be part of the job description.
But the question remains, how come individuals who are disciplined in so many areas of their lives fail so spectacularly in other areas?
Sadly, this is not limited to overeating. I am continuously asked why people who are religious and seemingly want to live a righteous life sometimes exhibit behavior that is unbecoming of who they purport to be – such as those who illegally and inconsiderately block traffic to “just run into the store for challah.” These contradictory paths of leading one’s life seem to point to a misalignment of core values.
Modern psychology has, of course, noticed this dichotomy and has put forth several theories as to why it occurs:
Far from ignoring the issue, Torah literature (especially in the teachings of Nachmanides and Maimonides) directly confronts the challenge of taking excesses pleasures within the permissible.
In his commentary on the verse “kedoshim tehiyu – you shall be holy […]” (Leviticus 19:2), Nachmanides (aka Ramban) provides one of the more famous psychological and ethical insights in Torah literature. He argues that a person could technically follow every specific law of the Torah – eating only kosher food and being properly married, etc. – yet still be a “naval bi-reshut ha-Torah – degenerate within the scope of what’s permitted in the Torah.” Here is commentary:
“The meaning of this is […] that the Torah has forbidden illicit sexual relationships and forbidden foods, but it has permitted intercourse between husband and wife and the eating of meat and wine. If so, a man of desire could find a place to be steeped in the lust of his wife or many wives, and be bibulous and gluttonous and speak as he pleases all sorts of profanities, since these things were not [explicitly] prohibited by the Torah. He could thus be a degenerate with the permission of the Torah.”
Thus, in Nachmanides’ view a person achieves a true holiness not by the mitzvot – commandments that he fulfills, but rather by how he controls his baser desires. This is done by maintaining a level of self-restraint that goes beyond the “black letter” of the law.
Maimonides (aka Rambam) lays out a foundational principle known as the “golden mean” – that a person should avoid extremes and live with balance. He writes that one should not be overly indulgent, or excessively ascetic. Rather, a person should train himself toward measured, disciplined moderation in all areas, including eating. He also explicitly warns against gluttony, even when the food is kosher and permitted.
He frames overeating as not merely unhealthy, but as a moral and intellectual flaw. This is because it dulls the mind and distances a person from clarity and wisdom. “A person should not eat until his stomach is full, but should leave about a quarter of his hunger […] for filling the stomach is harmful to the body, and it dulls the intellect” (Yad Hilchot De’ot 4:14-15).
Where psychology describes overindulgence as compensation, reward systems, and behavioral spillover, the Torah frames it as a lack of kedusha (sanctity) and an absence of self-mastery, which ultimately leads to a misalignment between one’s behavior and higher purpose. Living a truly religious life involves being disciplined with what’s forbidden and a personal and moral refinement in what’s permitted. Live with balance by showing restraint even in the permissible.
Of course, this week’s Torah reading is relevant to this very topic. The end of this week’s Torah reading discusses the laws of what is considered kosher and what is not. The word kosher actually means “fit for use,” so I felt it appropriate to discuss the concept of kashrut (kosher) and healthy eating here.
Fulfilling a true Torah lifestyle requires some granular understanding of our daily lives. This includes understanding and prioritizing healthy eating and healthy living. The clearest link between diet and cancer is through obesity.
Eating patterns that emphasize whole grains, fresh fruits and vegetables, and lean or plant-based proteins have shown the most consistent association with a lower risk of cardiovascular disease, diabetes, and cancer. One reason may be that people who follow these eating patterns have lower levels of insulin and inflammation, said Fred Tabung, a cancer epidemiologist at The Ohio State University College of Medicine and Comprehensive Cancer Center.
Rabbi Alexander Seinfeld, along with Dr. Daniel Grove, has written an important book on living a healthy life called Body and Soul – the Torah Path to Health, Wellness, and a Holy Life. There are many important principles to absorb, e.g. the harm that excess sugar does to our bodies, and the fact that there is a growing body of literature showing a clear link between what we eat and the likelihood of developing various cancers. Instead of relying on “super-foods” and antioxidants, we should focus on how long-term dietary habits affect our personal risk.
Another important and oft-overlooked component is physical fitness.
The Torah tells us, “v’nishmartem me’od lenafshoseichem – you should very carefully guard your souls” (Deuteronomy 4:15). Though in the Torah’s context it’s discussing idol worship, in several places the Talmud extends this principle to one’s physical health.
Thus, we are obligated to guard our health carefully. Too often people think of health as a secondary concern, something nice to work on if time permits (such as exercise and home cooked meals). But the Torah teaches otherwise. Our bodies are the vessel through which we serve the Almighty, care for our families, learn Torah, do mitzvot, and fulfill our purpose in this world. Protecting our health is not vanity; it is in service of God.
In my own effort to improve my health and lose weight, I have begun walking more consistently. Over time, I also started picking up the pace. What I found encouraging is that this simple change not only feels productive, but it appears to have meaningful benefits. Research suggests that fast walking, even as little as 15 minutes a day, may be associated with a far greater reduction in mortality than spending much longer walking at a very slow pace. In other words, effort and pace matter.
That is a powerful lesson in more ways than one. In our spiritual and physical lives, it is often not enough to merely be moving. Yes, direction matters, but so does intention, energy, and commitment. A person can go through life slowly drifting, or he can move with purpose. Even a small amount of focused effort can accomplish more than a great deal of passive motion. Go to www.fastwalker.com to learn more and read up on the relevant research.
Sometimes we imagine that meaningful change requires dramatic action. But often growth begins with something much smaller: one relatively small daily decision, done with consistency and energy. A person who walks with purpose is not only strengthening his body but, more importantly, is honoring the gift that the Almighty gave him.
May we all merit the wisdom to take care of ourselves properly, and through that, have the strength to serve God with greater vitality, clarity, and true joy.
Concluding the seven days of inauguration for the Mishkan (Portable Sanctuary), Aaron, the High Priest, brings sacrifices for himself and the entire nation. Nadav and Avihu, sons of Aaron, bring an incense offering of their own initiative, and are consumed by a heavenly fire (perhaps the only time when someone did something wrong and was immediately struck by “lightning”).
I saw few die of hunger, of eating – a hundred thousand.
- Benjamin Franklin
For the refuah of all those in our community who need it.
Please Hashem answer our prayers NOW!
