Key Takeaways
- “Sugar-free” is not carb-free — the flour and starch are usually still there.
- Check the serving size before anything else; a “3g net carb” bag is often 2.5 servings.
- Only subtract fiber, erythritol, and allulose from total carbs — maltitol counts about half like sugar.
- Words like “keto-friendly” and “all natural” are marketing, not regulated claims. The nutrition panel is the only part of the package that can’t spin.
Food brands know low-carb shoppers scan packages fast — and the front of the box is designed for exactly that scan. The four tricks below account for most of the “why did this stall my progress?” moments we hear about, and each one takes about five seconds to catch once you know where to look.
1. The “Sugar-Free” Trap: No Sugar Doesn’t Mean No Carbs
A sugar-free cookie is still a cookie. Take the sugar out of a recipe and the wheat flour, tapioca starch, and maltodextrin are all still in there — and your body treats those starches almost exactly like sugar. Maltodextrin actually has a higher glycemic index than table sugar.
Classic example: sugar-free sandwich cookies that come in at 18–20g of carbs per serving — within a few grams of the regular version. The label says “sugar-free” in big letters because that’s the only claim it can make.
The 5-second check: ignore the front of the package entirely and read the total carbohydrate line. If a “sugar-free” product still shows 15g+ total carbs, the sugar was replaced with starch, not removed.
2. The Serving-Size Shrink: When One Bag Is Secretly Three Servings
This is the oldest trick on the shelf. A snack advertises “only 4g net carbs!” — per serving. Then you flip the bag and find the serving is 28 grams and the bag holds 2.5 servings. Eat the bag like a normal human and you’ve had 10g, not 4g.
It shows up everywhere: nut mixes, keto granola, low-carb tortillas (“half a wrap” servings), and drink mixes. The numbers on the panel are honest — the portion they describe is not how anyone eats.
The 5-second check: read servings per container before you read anything else, and multiply. If the honest math still fits your daily target (our guide to how many carbs per day helps you set one), it’s a keeper.
3. The Net-Carb Shell Game: Not All Sugar Alcohols Subtract
“Net carbs” math is legitimate — fiber and certain sweeteners really don’t raise blood sugar. The trick is that some brands subtract sweeteners that do.
Maltitol is the big offender: it’s cheap, it tastes great, and your body absorbs roughly half of it like regular sugar. A bar that claims “2g net carbs” after subtracting 14g of maltitol is realistically closer to 8–9g. Erythritol and allulose, on the other hand, genuinely pass through — those subtractions are fair.
The 5-second check: find the sugar alcohol in the ingredients list. Erythritol, allulose, stevia, monk fruit — subtract freely. Maltitol, sorbitol, isomalt — count about half. Our net carbs guide walks through the full label math step by step.
4. The Health Halo: “Keto-Friendly” Is a Font, Not a Fact
“Keto-friendly.” “Low glycemic.” “All natural.” “Made with whole grains.” None of these phrases has a legal definition on a food package — any brand can print them on anything. There are “keto” granolas on mainstream shelves with 14g of net carbs per tiny serving.
The halo works because it gives you permission to stop reading. The front of the package answered your question, so you never flip it over — which is precisely the point of the design.
The 5-second check: treat every front-of-package claim as an ad, because it is one. The only formula that matters: total carbs − fiber − erythritol/allulose = real net carbs. Every product in our low carb snacks aisle is stocked with that math already done — but we’d still rather you check us on it. Once label-reading is a reflex, no package can talk you out of your own progress.