How to read a nutrition label for diabetes

The four lines that matter most, how to calculate net carbs, and the marketing tricks brands use to hide sugar.

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 13, 2026 4 min readEditorial policy

Most people read labels wrong. Here's the diabetic's 60-second method.

Step 1: serving size first

Always. A "150-calorie" granola bar that's actually 2 servings is 300 calories and 40g carbs. Brands inflate or deflate servings to make numbers look better.

Step 2: total carbs

This is the only carb number that matters for blood sugar. Ignore "sugar" alone — starch raises glucose just as fast.

Step 3: subtract fiber

Net carbs = total carbs − fiber. Fiber doesn't digest, so it doesn't raise blood sugar.

Step 4: check added sugars

The "Added Sugars" line separates natural sugars (e.g. lactose in milk) from refined sugars. A yogurt with 12g total sugar and 0g added sugar is fine. The same yogurt with 12g added sugar is dessert.

Sneaky names for added sugar

Anything ending in "-ose" (fructose, dextrose, maltose)
High-fructose corn syrup
Cane juice / cane crystals / evaporated cane juice
Agave nectar, brown rice syrup, barley malt
Maltodextrin (yes, it spikes glucose)
Honey, molasses (still sugar)

Marketing traps

**"No sugar added"** — may still contain juice concentrate, which is just sugar
**"Sugar-free"** — may use sugar alcohols that cause GI upset
**"Whole grain"** — only meaningful if it's the *first* ingredient
**"Low fat"** — usually means high carb to compensate
**"Made with real fruit"** — could be 1% real fruit

The shortcut

If a label takes more than 30 seconds to evaluate, the product is probably engineered. Real food rarely needs a label.

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.