Zero drinks aren’t a small fad in South Korea: the Korean zero drink market grew from about 163 billion won in 2018 to 1.278 trillion won in 2023, a spike of almost 8 times, in just five years. But do young people actually know what "zero" means? Or do they trust, rather blindly, what they purchase, based on the “zero” labels alone? 


Dohyun Park, a 16-year-old attending NLCS Jeju, said he drinks zero drinks a lot, especially when there's a 1+1 deal at franchised convenience stores. Park, though, doesn't really think that these drinks are automatically healthy. “I feel like the sweetener ingredients in zero drinks could be harmful in their own way,” he said. Gyubo Yoon, a 16-year-old student attending the same school, said something similar: he knows that sweeteners like stevia are used, but he doesn't at all know about its side effects.


On the other hand, many teenagers view zero drinks through a halo of healthiness. Soyule Shin, a 16-year-old attending an international school in Jeju Island, South Korea, admits that she assumes zero drinks are inherently better for her simply because they contain less sugar than conventional sodas. Similarly, Rihoo Kim, a 16-year-old at Sehwa High School, believes zero drinks are "healthier than regular ones," adding that most of his information comes from "social media and YouTube ads."


This consumer confusion among youth mirrors broader market trends. In an at-large consumer survey, when respondents were asked what a "zero" label actually signifies, only 33.6% of total respondents correctly identified "zero calorie." Teenagers were the only age group where a plurality (45.7%) mistakenly assumed "zero" automatically meant zero calories.


A "zero" label primarily means that no standard sugars (like sucrose or high-fructose corn syrup) were added. Instead, manufacturers replace sugar with alternative sweeteners—such as aspartame, sucralose, acesulfame potassium, or erythritol—to deliver sweetness without the associated calories or blood sugar spikes.


To prevent mislabeling and protect consumers, South Korea’s Ministry of Food and Drug Safety updated its labeling standards. Effective January 1, 2026, foods using alternative sweeteners in place of sugar that feature prominent claims like "Zero Sugar," "Sugar-Free," or "No Added Sugar" must display a "contains sweetener" warning along with exact calorie information directly adjacent to the claim.


Under these revised guidelines:

  • "Sugar-Free" / "Zero Sugar" / "Sugar Free": Can only be claimed if the sugar content is lowered or eliminated during manufacturing to less than 0.5 g per 100 g (or 100 mL) of food.
  • "No Added Sugar" / "Unsweetened": Can only be used if no sugars, functional sugar substitutes, or sugar-containing raw materials were added during production, and the natural sugar content was not increased through processes like enzymatic breakdown.


Despite stricter labeling, scientific questions remain: how do these drinks actually affect the human body, and are they genuinely healthy?


Professor Ji-hoon Kang, a food biotechnology expert at National Korea University of Transportation (HKNU), explains that on a sensory level, our bodies process sweetness identically regardless of the source. "Sweetness is perceived when sweet-tasting molecules react with the taste receptors on the tongue's taste buds," Kang notes. "This mechanism is the same for all sweet components, including sugar."


The key divergence happens after swallowing. While sugar is metabolized into glucose for energy—or stored as body fat when consumed in excess—non-nutritive sweeteners pass through the body without raising blood sugar or providing usable calories. This makes zero drinks a helpful tool for weight management and calorie reduction.


However, Professor Kang cautions against equating "zero sugar" with a "healthy food."


"While zero drinks can certainly aid in dieting because they lack sugar or high-fructose corn syrup, it is scientifically difficult to classify them as 'healthy foods,'" Kang said. "While we cannot say alternative sweeteners are 100% harmless, if consumed within the Acceptable Daily Intake (ADI) limits set through toxicity evaluations, their negative health impacts are minimal."


Kang emphasizes that staying within these safety thresholds is far easier than public anxiety suggests. For instance, aspartame’s ADI is set at 40 mg per kilogram of body weight per day. For an adult weighing 60 kg, the daily limit would be 2,400 mg. Given that a standard 250 mL can of zero cola contains roughly 43 mg of aspartame, an individual would need to drink up to 55 cans in a single day to reach the ADI limit—an nearly impossible amount for normal consumption.


Even recent headlines regarding sweetener side effects—such as the World Health Organization classifying aspartame as a Group 2B carcinogen, or studies suggesting sucralose alters gut microbiota—need to be viewed in context. "Group 2B classifications reflect the strength of scientific research available, not the absolute level of danger," Kang clarifies, noting that traditional Korean foods like kimchi are also in Group 2B.


Furthermore, neuroscience research suggests that drinking zero sodas can occasionally backfire by triggering sugar cravings. When the brain detects a sweet taste, it anticipates a dose of glucose; when that energy fails to arrive, it can cause the body to compensate by seeking out extra sugar in subsequent meals.


"When it comes to food, quantity is always what matters most," Professor Kang advises. "Rather than relying blindly on the word 'zero' on a label, wise consumers should inspect the nutrition facts and ingredient lists to suit their personal needs. For true health, water or tea remains the best choice, but enjoying zero drinks in moderation within a balanced lifestyle is perfectly safe."