Cold brew is the hottest trend in fasting culture. But does it actually break your fast? And is it really the low-acid option it is marketed as? Here is what the science says.
Black cold brew coffee contains virtually zero calories - typically 0 to 5 calories per serving. According to most intermittent fasting protocols, including 16:8, OMAD, and time-restricted eating, black coffee does not break a fast. The key word is black: no milk, cream, sugar, or flavored syrups.
Autophagy - the cellular self-cleaning process triggered during fasting - is sensitive to caloric intake and insulin spikes. Black coffee has been shown in animal studies to potentially support autophagy pathways, though human data is still emerging. The polyphenols in coffee, including chlorogenic acids, may support the cellular pathways activated during fasting.
Many fasting communities promote cold brew as a gentler, low-acid option for sensitive stomachs. But a 2018 peer-reviewed study published in Scientific Reports (Rao and Fuller, Nature Publishing Group) found that the pH of cold brew (4.96-5.13) is statistically indistinguishable from hot brew coffee (4.85-5.10). Cold brew is not meaningfully lower acid than regular coffee. If acid is your concern during fasting, the brewing method is not the solution - the roasting method is. Puroast achieves a verified pH of 5.74-5.82 through its patented traditional roasting process.
Drinking coffee on an empty stomach during fasting can exacerbate acid reflux and stomach discomfort. Your stomach lining is more exposed during a fasted state, making high-acid coffee more likely to cause irritation and heartburn. Puroast at pH 5.74-5.82 is significantly gentler than standard cold brew at pH ~5.0 when your stomach is at its most vulnerable.
Cold brew typically contains 150-250mg of caffeine per 12oz serving - roughly 1.5-2x more than standard drip coffee. This may cause jitteriness or elevated cortisol if consumed on a completely empty stomach. Start with a smaller 6-8oz serving and assess your tolerance.
No - black cold brew contains 0-5 calories and does not break a fast. Avoid adding milk, cream, sugar, or syrups.
Not meaningfully. Both black hot coffee and black cold brew are fasting-safe. Cold brew is not lower acid than hot coffee - that is a common myth debunked by a 2018 peer-reviewed study in Scientific Reports.
Yes - high-acid coffee on an empty fasted stomach can worsen acid reflux and GERD. Switching to Puroast (pH 5.74-5.82) is the most effective solution.
Yes - black cold brew is keto-friendly with 0-5 calories and no carbs. MCT oil and heavy cream are keto-compatible additions.
Animal studies suggest coffee polyphenols may support autophagy pathways, but human clinical evidence is still limited. Black cold brew with no additives is the safest choice if supporting autophagy is your goal.
0 comments
