Yom Kippur begins at sundown on Sunday, September 20, 2026, and ends at nightfall on Monday, September 21, 2026 [2]. If you have diabetes and are considering fasting, the honest starting point is this: the published clinical literature on religious fasting with diabetes comes from Ramadan research, not from Yom Kippur fasting. No published trial has measured diabetes outcomes during the Yom Kippur fast. Peninei Halakha says that on Yom Kippur only people whose lives may be in danger if they fast are exempt, because preservation of human life overrides the Torah's commandments [1]. The decision about whether you can fast safely belongs to your clinician and your rav, together, before the fast.
What the clinical literature actually covers
The International Diabetes Federation and the Diabetes and Ramadan International Alliance published practical guidelines in 2021 for diabetes care during Ramadan fasting [3]. The guidelines say that individuals with some illness and serious medical conditions, including some people with diabetes, can be exempted from fasting, yet many will fast anyway [3]. The guidelines emphasize that it is of paramount importance that people with diabetes who fast are given appropriate guidance and receive proper care [3].
That guidance exists because Ramadan daytime fasting is a documented medical event. A 2025 systematic review and meta-analysis examined GLP-1 receptor agonist use by people with type 2 diabetes during Ramadan daytime fasting [4]. The analysis covered 4 studies involving 754 subjects and measured during Ramadan data: compared with other glucose-lowering medicines, the GLP-1 receptor agonist group had a greater glycated hemoglobin reduction (mean difference 0.31 percentage points), a lower risk of documented symptomatic hypoglycemia (risk ratio 0.38), and 2.0 kg more weight loss, while gastrointestinal side effects such as nausea and vomiting were more frequent [4]. The authors describe the evidence as limited and call for larger trials [4].
These are Ramadan figures. Ramadan daytime fasting runs from dawn to sunset, a period much longer than the sundown-to-nightfall Yom Kippur fast. The medicines, the blood glucose patterns, the hypoglycemia risk, and the gastrointestinal effects measured during Ramadan cannot be read as predictions for Yom Kippur. The gap is real, and the honest answer is that your clinician and rav are the ones to consult.
What Peninei Halakha says about fasting when sick
Peninei Halakha says that on Yom Kippur even the infirm are obligated to fast because it is a Biblical command [1]. The exemption is narrow: only people whose lives may be in danger if they fast are exempt, because the preservation of human life overrides the Torah's commandments [1].
On the other fasts, which were instituted by the Rabbis, the rule differs. Peninei Halakha says that anyone who is sick is exempt from fasting even if the condition is not life-threatening [1]. In general, people whose pain or weakness precludes them from continuing their regular routine of life, forcing them to lie down, are considered sick [1].
Tisha B'Av occupies a middle ground. Peninei Halakha records the view that Tisha B'Av differs from the minor fasts, with only someone who is actually sick or liable to become sick because of the fast exempt on Tisha B'Av, while even someone in great pain is exempt from the minor fasts [1]. Peninei Halakha also records that many poskim do not make such a distinction [1].
These are the named positions in the halachic literature. Whether your situation fits the exemption on Yom Kippur is a question for your rav, who knows your condition, your community's practice, and the halachic authorities your community follows.
Medicine on a fast day
Peninei Halakha says that sick people who need to take medicine regularly, such as a person who suffers from a chronic disease, must continue taking their medicine even on a fast day [1]. If possible, one should swallow it without water [1]. Peninei Halakha notes that almost no medicine does any harm to those who take it without water [1].
If you cannot swallow pills without water, Peninei Halakha says that one should add something bitter to the water until it becomes undrinkable and use it to swallow the pill [1]. The bitter water is not considered food or drink in the halachic sense because it is undrinkable.
Your exact medicine list matters. Ask your pharmacist and clinician which forms you take and whether water is required for each one. That information, together with the halachic positions from Peninei Halakha, is what your rav needs to make a ruling for your situation.
What to ask your clinician before the fast
The decision to fast with diabetes is a medical decision that belongs to your clinician. Bring these questions to the appointment and write down the answers.
Before the appointment, gather your exact medicine list, including the names, forms (pill, liquid, injection), and how often you take each one. Bring your blood glucose log or the data from your meter if you have it.
At the appointment, ask these specific questions:
- Can I safely fast on Yom Kippur given my diabetes and my current medicine list?
- What warning signs mean I should break the fast immediately?
- How does my plan change on a no-food no-water day? (This matters because some medicines work differently with food, and some need water to swallow.)
- Which of my medicines can I take without water, and which ones require water?
- If I need to break the fast, what should I eat or drink first?
Write down every answer. If your clinician is unsure about a halachic question (like whether bitter water counts as breaking the fast), that is a question for your rav, not your clinician. Take the medical plan to your rav and ask for a ruling on your specific situation.
Here is a checklist to bring to your clinician appointment and to your rav.
| Before the appointment | At the appointment | After the appointment |
|---|---|---|
| Gather your exact medicine list with names, forms, and frequency | Ask if you can safely fast given your diabetes and medicine list | Write down your clinician's answers |
| Bring your blood glucose log or meter data | Ask what warning signs mean you should break the fast | Take the medical plan to your rav |
| List any recent blood glucose patterns or concerns | Ask how your plan changes on a no-food no-water day | Ask your rav for a ruling on your specific situation |
| Ask which medicines can be taken without water | ||
| Ask what to eat or drink first if you break the fast |
Refuah publishes free guides on medication and fasting and GLP-1 medicines and religious fasts to help you prepare for these conversations. The guides hub collects related resources in one place. Refuah is education only today, with no care delivered, no prescriptions, no testing, and no clinical team. The plan is that before care launches, a rav will review every fasting page and a clinician will co-sign every fasting protocol; those roles are open and unfilled right now.
The halachic frame
Peninei Halakha's statement on preservation of life is the foundation of every fasting decision with a medical condition: the preservation of human life overrides the Torah's commandments [1]. That principle means no fast is worth a medical risk. If your clinician says fasting is unsafe for you, that is the medical answer. Whether that medical answer changes the halachic obligation is a question for your rav.
Jewish communities are plural. Observance, custom and halachic authority differ across and within communities. Your rav may hold differently from any position this article records. The question to bring is your own situation: your exact diabetes type, your exact medicine list, your clinician's assessment of the risk, and your community's practice. Your rav will rule on that.
What to do next
- Schedule a clinician appointment at least 2 weeks before Yom Kippur.
- Gather your exact medicine list, including names, forms, and frequency, and bring it to the appointment.
- Bring your blood glucose log or meter data if you have it.
- Ask your clinician the 5 questions listed above and write down the answers.
- Ask your clinician what warning signs mean you should break the fast immediately.
- Take the medical plan to your rav and ask for a ruling on your specific situation.
Sources
- Peninei Halakha, the infirm are exempt from fasting, accessed 2026-08-09, https://ph.yhb.org.il/en/05-07-07/
- Hebcal, Yom Kippur 2026, accessed 2026-08-09, https://www.hebcal.com/holidays/yom-kippur-2026
- IDF-DAR, Diabetes and Ramadan Practical Guidelines 2021, PubMed, accessed 2026-08-09, https://pubmed.ncbi.nlm.nih.gov/35016991/
- GLP-1 receptor agonists during Ramadan fasting, 2025 systematic review and meta-analysis, PubMed, accessed 2026-08-09, https://pubmed.ncbi.nlm.nih.gov/40900863/