Does sugar cause acne? High-glycemic food, fast food and your skin
Possibly. Two small trials found a low-glycemic diet reduced acne, and sugary drinks are linked to breakouts, but it isn't proven and some studies found no link.
The short answer
There’s some evidence that sugary, high-glycemic food can make acne worse, but it isn’t proven. Two small randomised trials found that a low-glycemic diet reduced acne, and several observational studies link high-glycemic food and sugary drinks to acne. But the trials were tiny and short, the people on the diet also lost weight, and some studies found no link at all. Diet on its own is very unlikely to clear acne, but it can be worth testing on your own skin.
What the research says
High-glycemic foods are the ones that raise your blood sugar quickly: white bread, white rice, fries, pastries, sugary drinks. The American Academy of Dermatology says findings from small studies suggest a low-glycemic diet may reduce acne. Its explanation is that blood sugar spikes cause inflammation and make your skin produce more oil, both of which can lead to acne. That’s a plausible mechanism, not something that’s been proven in people with acne. The same page says other studies have not found a connection between a high-glycemic diet and acne, so more research is needed.
The best-known trial is a 2007 randomised controlled trial of 43 young men with acne in Australia. After 12 weeks, the group on a low-glycemic-load diet had a bigger drop in spots (about 24 fewer, compared with 12 fewer in the comparison group). But the low-glycemic group also lost more weight, and the authors said more studies were needed to separate the effect of weight loss from the diet itself. A 2012 trial of 32 people in Korea found a similar improvement after 10 weeks on a low-glycemic diet. Two small trials agreeing is encouraging, but neither tells us much about women, older adults or people with severe acne.
A 2022 systematic review in JAAD International concluded that high-glycemic diets have a “modest yet significant” effect on acne, and that more randomised trials are needed.
For sugary drinks and sugary foods, the evidence is observational. A large French study of about 24,000 adults linked fatty and sugary foods and sugary drinks to current acne, and a 2026 survey of 819 Chinese college students found sugary drinks were linked to higher odds of acne, alongside stress, poor sleep and other habits. Both took a single snapshot of people’s habits and skin, so they can’t show that sugar caused the acne.
Why it varies from person to person
How your body handles sugar differs from person to person, and so does how much of your diet is high-glycemic in the first place. Cutting sugar from a diet that’s already mostly vegetables and lentils changes much less than cutting it from a diet of fizzy drinks and takeaways.
Sugary food also travels with other suspects. Milkshakes and ice cream are dairy. Fast food often means late nights, alcohol or a stressful week. Cravings can spike before your period. If you notice breakouts after a weekend of takeaways, any of those could be the real cause, and only a careful test can separate them.
How to test it on your own skin
SkinTheory turns a hunch into an experiment, so you can get scientific about your skin and isolate the real cause instead of guessing. The AAD suggests the same idea: notice whether a food seems to trigger breakouts, and what happens when you don’t have it.
- Hypothesis. Pick something specific, for example “Does fast food make me break out within a few days?” or “Does cutting sugary drinks reduce my pimple count?” Set it up as a hypothesis in SkinTheory.
- Track. Each entry, take your three skin photos and log skin feeling, mood and pimple count, plus the Fast food tracker. If you’re also curious about drinks, log Water too. Keep your skincare routine, products and everything else you can control the same.
- Analyze. After about 21 entries (3 weeks if you log daily), look at the graphs to see whether pimple count rises a day or two after fast-food days, and scroll the photo timeline. Acne changes slowly (the AAD says even proven treatments take at least 6 to 8 weeks to reduce breakouts, and the diet trials above ran for 10 to 12 weeks), so a longer run gives a clearer answer.
Everything stays private in SkinTheory: photos never go to your camera roll, and your history is yours to keep on your phone indefinitely. Fast food is a Lab+ tracker; you can use any two Lab+ trackers for free at a time.
Tips while you test
- Change one thing at a time. Cutting sugar, dairy and alcohol in the same week makes a clear result impossible.
- Look for a delay. If food affects your skin at all, a change may take days or weeks to show, so don’t judge on the same day.
- Don’t swap one high-glycemic food for another, like dropping sweets but eating more white bread.
- If you have diabetes or another health condition, are pregnant, or have a history of disordered eating, talk to a doctor or dietitian before changing what you eat.
- If your acne is painful, scarring or affecting how you feel, see a doctor or dermatologist rather than relying on diet changes.
Food is only one part of the picture. If the pattern lines up with milk, read does dairy cause acne; if it lines up with nights out, see alcohol. And if you’re on a treatment, log food alongside it so you know whether it’s the treatment or your life that’s changing your skin.
Questions people ask
What counts as high-glycemic food?
Foods that raise your blood sugar quickly. The AAD’s examples include white bread, white rice, white potatoes and fries, corn flakes, puffed rice, potato chips, doughnuts and pastries, and sugary drinks such as milkshakes. Low-glycemic foods include most fresh vegetables, some fresh fruits, beans and steel-cut oats.
Does chocolate cause acne?
Nobody knows for sure. One tiny trial of 13 young men with acne found more spots within a week of swallowing pure cocoa capsules, but it was far too small and short to settle the question. Chocolate also usually comes with sugar and milk, so if you suspect it, track it for a few weeks with everything else kept the same.
Will cutting sugar clear my acne?
Probably not on its own. The AAD says keeping your skin clear takes more than a diet change, and that skin care and acne medication help prevent new breakouts. Small trials suggest eating fewer high-glycemic foods might reduce acne a little for some people, but that hasn’t been proven.
Is fast food bad for acne?
There’s very little research on fast food itself. A large French study linked fatty and sugary foods and sugary drinks to acne in adults, but it was observational and can’t show cause and effect. SkinTheory has a Fast food tracker so you can see whether it lines up with your own breakouts.
Sources and further reading
- Can the right diet get rid of acne?, American Academy of Dermatology
- A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial, American Journal of Clinical Nutrition (2007), via PubMed
- Clinical and histological effect of a low glycaemic load diet in treatment of acne vulgaris in Korean patients: a randomized, controlled trial, Acta Dermato-Venereologica (2012), via PubMed
- Diet and acne: A systematic review, JAAD International (2022), via PubMed
- Association Between Adult Acne and Dietary Behaviors: Findings From the NutriNet-Santé Prospective Cohort Study, JAMA Dermatology (2020), via PubMed
- Mediating Effect of Sleep Quality on the Association Between Psychological Stress and Acne Vulgaris in Chinese College Students: A Cross-Sectional Study, Healthcare (2026), via PubMed
- Double-blind, Placebo-controlled Study Assessing the Effect of Chocolate Consumption in Subjects with a History of Acne Vulgaris, Journal of Clinical and Aesthetic Dermatology (2014), via PubMed
This guide is general information written by the SkinTheory team, not medical advice. SkinTheory isn’t a medical device. For diagnosis, prescriptions or side effects, talk to a dermatologist or doctor, and bring your SkinTheory log along.