Coffee and blood sugar: what you need to know

Why coffee can raise glucose in some people, the impact of milk and sweeteners, and the best ways to take your morning brew.

Written by

Carb Lens Editorial

Nutrition writers & product team

Medically reviewed by

Dr. Alicia Nguyen, RD, CDCES

Registered Dietitian · Certified Diabetes Care & Education Specialist · 12+ years clinical experience

Published June 21, 2026 3 min readEditorial policy

Black coffee has zero carbs — but its effect on blood sugar is more nuanced than you'd expect.

The caffeine paradox

Caffeine can temporarily raise blood sugar in some people through cortisol and adrenaline release. The effect is most pronounced in: - People with type 2 diabetes - After fasting (morning coffee) - Those sensitive to caffeine

Long-term, coffee drinkers actually have a lower risk of developing type 2 diabetes. The acute spike doesn't translate to chronic harm.

What you add matters more

**Black coffee**: 0g carbs, possible mild glucose bump
**Coffee + splash of cream**: 0g carbs, no glucose effect
**Coffee + 1 tsp sugar**: 4g carbs
**Latte (8 oz, whole milk)**: 12g carbs
**Vanilla latte**: 25g+ carbs
**Frappuccino (16 oz)**: 50–65g carbs
**Pumpkin spice latte (grande)**: 50g+ carbs

The fix for sweet-coffee lovers

Espresso + heavy cream + a few drops of stevia
Iced coffee with unsweetened almond milk + monk fruit + cinnamon
Cold brew is naturally smoother and needs less sweetener

Decaf

Eliminates the caffeine bump for sensitive people. Same antioxidant profile.

When to skip coffee

Within 2 hours of a glucose test (can skew results)
After 2 PM if you have sleep issues (sleep matters more than coffee)
If you notice consistent fasting glucose rises after morning coffee

About the author

Carb Lens Editorial — Nutrition writers & product team. The Carb Lens editorial team writes practical, source-checked guides on carbs, blood sugar, and everyday nutrition. Every article is drafted by our writers and cross-referenced against USDA FoodData Central and peer-reviewed clinical guidelines.

How we source and review this article

Nutrition figures come from the USDA FoodData Central database. Blood-sugar and glycemic-load framing follows guidance from the American Diabetes Association and World Health Organization healthy-diet recommendations. Every article is medically reviewed by Dr. Alicia Nguyen, RD, CDCES before publishing and re-checked on a rolling basis. See our full editorial & medical review policy.

This article is for general information and is not a substitute for medical advice. If you're managing diabetes or another condition, always defer to your care team.