Does Zero-Sugar Cola Help You Diet? What the Research and Korean Medicine Both Suggest
My digestive tract is the sensitive sort, so food tends to announce its effects on me quickly. The first time I drank a zero-sugar carbonated drink, I noticed a strange quality — sweet, yet somehow less satisfying — but nothing much happened. Once I started drinking it often, a queasy sort of aversion set in, and I had the distinct feeling that my digestive system was being thrown off. The first couple of times, I think it did help with dieting. Later, it felt as though it were disturbing my body and coaxing me into cycles of skipping meals and then overeating. So I went looking at the research — and at what Korean Traditional Medicine (KTM), the traditional healing system of Korea also known as Hanbang (한방), would say about a sweetness with nothing behind it.
In Summary
- Findings are mixed — some studies point the other way — so no verdict here is absolute. But the reported downsides are more numerous than most people expect.
- Studies have linked artificially sweetened drinks to increased waist circumference over time, effects on glycemic and hormonal responses, altered gut microbiota and glucose intolerance, headache in susceptible people, allergic reactions, and increased sugar craving.
- In KTM, the sweet flavor slows metabolism — and zero-sugar drinks deliver that sweetness stripped of the nutritive essence (수곡정미) that real food carries.
- So the spleen is called to work and finds nothing to transform: it labours in vain. Meanwhile the five organs, still needing actual nourishment, end up calling for food — which is why you eat more later.
- It follows that drinking a zero-sugar drink alongside ordinary food, which does carry nutritive essence, is somewhat better than drinking it on its own.
- Practical: unsweetened sparkling water worked for me, and my symptoms disappeared. When a craving hits, take a few deep breaths — better still, don’t buy it. If it is still too hard, have a small amount of a normally sugared drink.
- Bottom line: an occasional one can help a diet, but over the long run it may add weight and may not serve your health.
What the Research Says
When I searched, I found that results run in both directions, so nothing here can be called always true. Still, the side effects reported were more extensive than I had assumed. Diet soda intake has been associated with long-term increases in waist circumference in older adults (Fowler et al., 2015). Sucralose has been shown to affect glycemic and hormonal responses to an oral glucose load — a signal toward insulin resistance (Pepino et al., 2013). Artificial sweeteners have been reported to induce glucose intolerance by altering the gut microbiota (Suez et al., 2014, Nature). On the neurological side, aspartame has been described as a trigger for headache in susceptible patients (Newman & Lipton, 2001), and artificial sweeteners appear among the agents investigated in recurrent urticaria (Juhlin, 1987). Sweeteners have also been discussed as increasing appetite through the neurobiology of sugar craving — the “gain weight by going diet?” problem (Yang, 2010). And there have been experimental carcinogenicity concerns raised in rodent feeding studies of aspartame (Soffritti et al., 2006). Taken together, that is a longer list of question marks than a “free” drink ought to carry.
The Korean-Medicine Reading: A Sweetness With Nothing Behind It
KTM gives a clean account of why this happens. In KTM, the sweet flavor is the taste that slows the pace of metabolism. Ordinarily, sweetness arrives attached to something — real food carries what KTM calls nutritive essence (수곡정미, 水穀精微), the refined substance drawn out of grain and food. A zero-sugar drink delivers the flavor and strips the essence away.
That is where the trouble starts. Tasting sweetness, the spleen (脾) is called to do its work of transforming and distributing — and finds there is nothing there to transform. It labours in vain, spinning its wheels over an empty load. Meanwhile the five organs, which still need actual nourishment, have received none: so they go on calling for food. That call is what you feel later as hunger, and it is why a “free” drink so often ends with you eating more than you meant to. And if, in that state, you force yourself to eat less instead, the deprivation generates its own damage and its own stress.
One practical corollary follows from this. If you are going to have a zero-sugar drink, having it alongside ordinary food — food that does carry nutritive essence — is somewhat better than drinking it on its own, because at least the spleen has something real to work on rather than labouring over nothing. (The sweetness can still slow the metabolism of that meal, so this is a lesser evil rather than a good.) Drunk alone, it moves the problem downstream rather than solving it.
What I Do Instead
These days I drink sparkling water with no sweetener in it, and the symptoms that used to bother me have all disappeared. As for how to endure the pull of sweetness: when the urge comes, I take a few deep breaths. The better method, honestly, is simply not to buy it — that solves the problem at the source. And if it is still too hard, then have a little of a normally sugared drink rather than a lot of the artificial one.
In Summary
Having one occasionally can help a diet, but over the long term zero-sugar drinks may add weight and may not be good for your health. The KTM reading is simple: sweetness without nutritive essence sets the spleen to work on nothing, while the organs that need feeding keep calling for food — so if you do drink one, drink it with a real meal rather than alone. I would like to be the sort of person who can eat anything without consequence — but the truth is that while the type of food matters, in many cases what matters more is the state of mind you eat in and how you move your body. So: keep the sweetness honest, drink water or plain sparkling water where you can, and above all, eat simply and with a glad heart.
Related reading: Why Chewing Matters · GLP-1 Drugs and the Pancreas · Sugar and Constitutional Type
This article reflects the clinical observations and teaching practice of Professor Seungho Baek, Professor of Korean Medicine at Dongguk University College of Korean Medicine, specializing in Pathology and Oncology.
