Deceptive Math in Public Health: Why the Codex 25% Nutrient Comparative Claim Standard Fails Global Sugar Reduction Goals

Imagine walking down a grocery aisle, reaching for a can of soda, and seeing a bright label that promises "Less Sugar." Your brain registers this as a win, a small step toward a healthier choice. This reaction is not accidental; it is a well-understood psychological trick known as the "healthy halo" effect. When a product carries a claim of improvement, consumers tend to perceive the entire item as safer or more nutritious, often overlooking the fact that the product might still be loaded with harmful ingredients. This cognitive bias is the central problem tackled by a new analysis from researchers at the University of Abuja and the Africa Centre of Excellence for Mycotoxin and Food Safety. They are looking at a specific rule that governs how food companies make these claims, a rule that was designed to help people but may actually be helping the wrong people: the manufacturers of sugary drinks.

The rule in question comes from the Codex Alimentarius, an international collection of food standards that acts as a global benchmark for safety and labeling. For decades, this standard has dictated that a food product can legally claim to have "less" of a nutrient, such as sugar, if it contains at least 25 percent less of that nutrient than the original version. On paper, this seems like a straightforward mathematical victory for public health. If a drink has a lot of sugar, and the company cuts that amount by a quarter, the label is allowed to say "reduced." However, the researchers argue that this rule operates in a vacuum, ignoring the reality of how much sugar is actually in the drink to begin with. The standard focuses entirely on the percentage of the cut, not the final amount left in the glass.

To test how this plays out in the real world, the team built a mathematical model using a typical carbonated soft drink found in markets around the globe. They started with a standard baseline: a drink containing 10.6 grams of sugar in every 100 milliliters. This is a common concentration for many popular sodas. Under the current international rules, a manufacturer only needs to reduce this amount by 25 percent to earn the right to put a "Less Sugar" sticker on the can. The researchers calculated what happens when a company follows this rule to the letter. A 25 percent reduction brings the sugar content down to 7.95 grams per 100 milliliters. Mathematically, the company has complied with the law. The label is truthful. The reduction is real.

But the story changes when you look at what a person actually drinks. Most people do not sip a drink by the 100-milliliter measure; they consume a standard serving, which is typically a 250-milliliter can or cup. When the researchers calculated the total sugar in that single serving of the "reduced" drink, they found it contained nearly 20 grams of sugar. While this is less than the original 26.5 grams, it remains a massive dose of free sugar. To put this in perspective, the World Health Organization suggests that adults should ideally limit their daily intake of free sugars to 25 grams for optimal health, with a maximum limit of 50 grams. By drinking just one can of this "improved" soda, a person consumes almost 80 percent of the ideal daily limit and nearly 40 percent of the maximum limit. The drink has been reduced, yet it remains a primary vehicle for delivering a dangerous amount of sugar in a single sitting.

The researchers argue that this gap between the percentage reduction and the absolute amount creates a dangerous loophole. Because the label says "Less Sugar," the consumer's brain is tricked into thinking the drink is now a healthy choice. This "healthy halo" encourages people to drink more of it or drink it more often, believing they are making a responsible decision. The result is that the public health goal of reducing sugar consumption is undermined. The drink remains highly concentrated with sugar, and the marketing claim acts as a shield that protects the product from criticism while encouraging consumption.

The paper also explores why this system is so difficult to change. The food industry argues that sugar is not just a sweetener but a structural ingredient that gives soda its texture and taste. They claim that cutting sugar by more than 25 percent would ruin the flavor, forcing them to use artificial sweeteners, which are themselves controversial. Furthermore, companies warn that if they cannot market their products as "reduced," they will stop investing in reformulation altogether, leaving the high-sugar versions unchanged. There are also legal hurdles; in many countries, companies argue that banning a truthful statement about a 25 percent reduction violates their right to free speech. On the international stage, if one country tries to set a stricter limit, it could face trade disputes, as other nations might claim the new rule is an unfair barrier to commerce designed to protect local industries rather than public health.

To solve this, the authors propose a new system called a "Dual-Gated Claim Framework." Instead of relying on a single percentage cut, they suggest that a product must pass two tests to earn a "Less Sugar" label. The first test is the existing 25 percent reduction, which ensures the company is actually trying to improve the product. The second test is a hard ceiling on the final amount of sugar. For liquid drinks, they recommend that the final product cannot contain more than 5 grams of sugar per 100 milliliters to qualify for the claim. Under this new rule, the soda in their example, which still has 7.95 grams per 100 milliliters, would be forbidden from using the "Less Sugar" label, no matter how much it was reduced from the original.

The researchers also suggest a visual fix to stop the "healthy halo" effect. They propose that if a product is allowed to make a claim, the label must show the exact numbers in plain sight, using the same size and style of text as the claim itself. Instead of a big, bold "Less Sugar," the label would have to read something like "Reduced from 10.6 grams to 7.95 grams," with the numbers just as prominent as the words. This forces the consumer to see the actual amount of sugar they are getting, rather than just the abstract idea of a reduction. The authors believe that by combining a strict limit on the final sugar content with clear, honest labeling, regulators can close the loophole that currently allows sugary drinks to masquerade as healthy choices, ensuring that marketing claims align with the actual health of the product.