What Is Zero Sugar? | FDA Rules Explained

Walk down any grocery aisle and the packages shout “zero sugar” at you — from sodas to protein bars to salad dressing. The phrase sounds absolute, but the truth is more nuanced. Under U.S. Food and Drug Administration rules, “zero sugar” is a marketing-style phrasing that maps to the FDA’s official “sugar free” claim, which allows up to 0.49 grams of sugar per serving. Here’s what that actually means for your grocery decisions and your diet.

The Official FDA Definition

The FDA sets a specific threshold for when a food can carry the “sugar free” label. The product must contain less than 0.5 grams of sugars per reference amount customarily consumed (RACC) and per labeled serving. For meals and main dishes, the same 0.5-gram limit applies per labeled serving.

The label also carries a second requirement: the food cannot contain an ingredient that is sugar or generally understood to contain sugars, unless the ingredient list is followed by an asterisked note like “adds a trivial amount of sugar” or “adds a negligible amount of sugar.” That’s why you’ll see those footnotes on some products — the manufacturer is stating that a small sugar-containing ingredient slips in but stays under the FDA’s threshold.

One more condition applies: for a “sugar free” claim, the food must meet FDA calorie disclosure rules, such as being labeled low or reduced calorie, or carrying a statement like “not a low calorie food.”

What “0 Grams” On The Label Really Means

Because the FDA allows products below 0.5 grams of sugar per serving to round down and declare “0 g” on the Nutrition Facts panel, a package showing exactly 0 grams may still contain a small amount of sugar. The rounding rule means a product can legally display a zero while carrying nearly half a gram per serving.

That sounds concerning, but the practical difference is tiny. Even if a product contains the maximum allowed 0.49 grams per serving, you’d need several servings to accumulate even a single gram of sugar. For most people, that’s negligible in the context of a normal diet.

Zero Sugar vs. No Added Sugar

A frequent source of confusion is the difference between “zero sugar” and “no added sugar.” These claims address different things and are not interchangeable.

• No added sugar: No sugar or sugar-containing ingredient was added during processing, but the food can still contain naturally occurring sugars. Milk with no added sugar, for example, still contains lactose.

This difference matters if you’re tracking sugar intake for diabetes management or low-carb diets. A product labeled “no added sugar” can still carry meaningful sugar from natural sources, so checking the Nutrition Facts panel is essential.

Zero Sugar And Your Diet

The “zero sugar” claim says nothing about overall nutrition, carbohydrate content, sweeteners used, or suitability for specific diets. Many zero-sugar products rely on artificial sweeteners or sugar alcohols, which affect people differently. Some sugar alcohols can cause digestive discomfort in larger amounts, and their carbohydrate contribution varies.

For practical purposes, zero-sugar products can support a lower-sugar eating pattern when used thoughtfully. The two common mistakes shoppers make are assuming zero sugar means no sugars at all and confusing it with “no added sugar.” Both errors are easy to avoid once you know the rules above.

If you’re building a lower-sugar pantry and want specific product picks, our roundup of best zero sugar foods lists options that genuinely fit the label.

The FDA’s own guidance documents this framework, including the agency’s food labeling guide and letters to manufacturers on sugar-free claims. Michigan State University Extension also publishes a plain-language breakdown of sugar label claims for consumers. When in doubt about any product, the full Nutrition Facts panel and ingredient list tell the real story — the front-of-package claim only gives you part of it.