Why is it so hard to know what's in your food?
You'd think it would be simple. Pick up a product, check the label, done. But it's not.
Manufacturers use over 60 different names for added sugar — maltodextrin, dextrose, evaporated cane juice, rice syrup — and most of us wouldn't recognize them. Added sugar hides in bread, pasta sauce, salad dressing, low-fat yogurt, granola bars, oat milk, barbecue sauce, and even condiments like ketchup. See our list of 75+ processed foods with hidden sugar for the full breakdown.
The good news? You don't need a nutrition degree to figure it out. Here are 6 ways to check — starting with the easiest.
6 ways to test for sugar in food
We've ordered these from easiest to most advanced. Most people only need Method 1.
Use a Sugar Scanner App (Easiest)
This is the fastest way to check any product for added sugar. Instead of memorizing sugar names or squinting at tiny labels, you just take a photo of the ingredient list and let AI do the work.
How it works:
- Open the app and snap a photo of the ingredient label
- AI reads the text and checks it against 60+ known sugar names
- You get a clear answer: added sugar found, or not
The whole process takes about 3 seconds — faster than finding the nutrition panel and doing the math yourself.
Our pick: SugarFlag is built specifically for this. It doesn't try to be a full nutrition tracker — it answers one question: does this product have added sugar? That's it.
- Instant results (3 seconds)
- No nutrition knowledge needed
- Catches all 60+ sugar aliases
- Works while you shop
- Requires smartphone
- Needs a readable ingredient label
SugarFlag is now available on the App Store.
Download it today — your first 5 scans are free.
Check the Nutrition Facts Label
If you prefer doing it yourself, the "Added Sugars" line on the Nutrition Facts panel is your best friend. Since 2020, U.S. food manufacturers are required to list added sugars separately from total sugars.
How to read it:
- Total Sugars = natural sugars + added sugars
- Added Sugars = sugars added during processing
- Check the % Daily Value — 20% or more is high
Quick rule: More than 5g of added sugar per serving? That's a sugary product for everyday eating.
4g of sugar = 1 teaspoon. That one number makes labels click. A yogurt with 20g added sugar? That's 5 teaspoons. A can of soda with 39g? Nearly 10 teaspoons.
Picturing sugar in teaspoons makes label numbers real — and much harder to ignore.
- Free and always available
- Most accurate for packaged foods
- Shows exact gram amounts
- Only works for packaged foods
- Serving sizes can be misleading
- "Added Sugars" line not available in all countries
Scan the Ingredient List for Sugar Aliases
No "Added Sugars" line? You can still check by reading the ingredient list. Ingredients are listed by weight, so if sugar (or a sugar alias) appears in the first 3-5 ingredients, it's a major component.
Common sugar aliases to watch for:
- "-ose" endings: glucose, fructose, dextrose, maltose, sucrose
- Syrups: corn syrup, high-fructose corn syrup, rice syrup, malt syrup
- "Natural" sugars: honey, agave, maple syrup, coconut sugar
- Concentrates: fruit juice concentrate, apple juice concentrate
- Others: molasses, cane juice, barley malt, dextrin
Watch for this trick: Some manufacturers split sugar into 2 or more types so each one appears lower on the list. If you spot multiple sugar sources, the product likely has significant added sugar.
- Low-fat yogurt — often replaces fat with sugar (12–18g per serving)
- Barbecue sauce — can be 30–40% sugar by weight
- Oat milk — contains maltose from the oat processing
- Granola bars — often marketed as healthy, 8–12g added sugar
- Ketchup — roughly 4g sugar per tablespoon
For the full list, see our guide to detecting added sugar in processed foods — including a printable checklist you can take to the store.
- Works for any labeled product
- Reveals hidden sugars
- Shows sugar quality/type
- Requires memorizing 60+ names
- No exact quantities
- Time-consuming in the store
For specific situations
Use a Brix Refractometer (Liquids Only)
A Brix refractometer measures sugar concentration in liquids by analyzing how light bends through a sample. It's commonly used by winemakers and juice producers — handy if you make your own juices or want to test beverages.
You place a few drops on the prism, look through the eyepiece, and read the Brix value. 10 Brix = roughly 10% sugar (10g per 100ml).
- Accurate for liquids ($15-40)
- Reusable, no batteries needed
- Only works on liquids
- Measures total sugars, not added
Glucose Test Strips (Quick Screening)
Pharmacy glucose test strips can give a rough yes/no indication of sugar in liquid foods. They're cheap (~$5 for 50 strips) but only detect glucose — not fructose or sucrose — so they're best for quick screening, not accurate measurement.
- Very cheap and fast
- Easy to find at any pharmacy
- Only detects glucose
- Not designed for food testing
Benedict's Test (Laboratory Method)
Benedict's test is a classic chemistry method used in labs and school science classes to detect reducing sugars (glucose, fructose, maltose) in a food sample. If you've ever done a biology practical at school, this might ring a bell.
How it works: dissolve or blend a food sample in water, add a few drops of Benedict's reagent (a blue copper sulfate solution), and heat the mixture. If reducing sugars are present, the solution changes color — from blue → green → yellow → orange → red, depending on how much sugar is in the sample.
A related method, Fehling's test, works on the same principle and is sometimes used interchangeably in educational settings.
- Scientifically accurate and well-established
- Used in labs and schools worldwide
- Semi-quantitative (color intensity = sugar level)
- Requires reagents and a heat source
- Not practical for grocery shopping
- Only detects reducing sugars (misses sucrose)
Which method is right for you?
Here's a quick comparison. For most people, Method 1 covers everything you need.
| Method | Best For | Cost | Speed |
|---|---|---|---|
| Sugar Scanner App | Everyday grocery shopping | Free to start | 3 seconds |
| Nutrition Label | Checking exact sugar grams | Free | 30-60 seconds |
| Ingredient Scan | Spotting hidden sugar names | Free | 1-3 minutes |
| Refractometer | Homemade juices, liquids | $15-40 | 2-3 minutes |
| Glucose Strips | Rough screening of liquids | ~$5 | 30 seconds |
| Benedict's Test | Lab or school experiments | $10-20 | 5-10 minutes |
The bottom line
You don't need a chemistry lab to know what's in your food. For most people, a scanner app handles 95% of what you need — instantly, at the store, with zero effort.
The manual methods (labels, ingredient lists) are great to understand, but let's be honest: when you're shopping with a full cart and limited time, you need something that takes 3 seconds, not 3 minutes.
The best method is the one you'll actually use. And the easier it is, the more likely you are to stick with it.