Diet and Acne: What Studies Say About Sugar, Dairy and Chocolate

Diet probably plays a small role in acne for some people, but it’s not the main cause, and no diet has been shown to clear acne on its own. The best evidence points to high-glycemic-load diets (lots of sugary and refined-carb foods) and, less convincingly, milk. The evidence on chocolate and whey protein is thin. The American Academy of Dermatology’s 2024 guideline found available evidence was insufficient to develop recommendations for dietary changes, and the UK’s NICE guideline tells clinicians to advise that there is not enough evidence to support specific diets for treating acne. Here’s what the studies actually show, and how much weight each finding can bear.

What do acne guidelines say about diet?

Both major guidelines land in the same place: interesting signals, not enough proof to prescribe a diet. When the AAD published its updated acne guideline in January 2024, it said the evidence was too weak to make recommendations on dietary changes, or alternative therapies such as vitamins or plant-based products. The guideline’s work group listed dietary interventions for the treatment of acne among its important evidence gaps. The guideline’s actual recommendations are about medicines: it gives strong recommendations for benzoyl peroxide, topical retinoids, topical antibiotics and oral doxycycline.

NICE’s 2021 guideline (NG198) is blunter, with a single diet recommendation: tell people there is not enough evidence to support specific diets for treating acne. The AAD’s patient advice is softer. It says diet may play a role in causing your breakouts or worsening your acne, but that keeping skin clear requires more than a diet change.

How strong is the evidence for each food? (Quick table)

This is my plain-English reading of the evidence, not an official grading. “Low” means the finding could easily change with better studies.

Do sugar and high-glycemic foods cause acne?

This is the strongest diet link we have, and it’s still modest. The key experiment is an Australian randomized trial of 43 young men aged 15 to 25. Over 12 weeks, those on a low-glycemic-load diet saw total lesion counts fall by an average of 23.5 lesions, versus 12.0 on the control diet. There’s a catch the authors flagged themselves: the low-glycemic group also lost more weight (2.9 kg versus a 0.5 kg gain) and improved their insulin sensitivity, so it’s hard to say whether the food itself or the weight loss drove the change.

A Korean trial randomized 32 people with mild to moderate acne to a low-glycemic-load diet or a control diet for 10 weeks. The diet group had significant improvement in both non-inflammatory and inflammatory lesions, and skin biopsies showed smaller oil glands and less inflammation. A 2022 systematic review of 34 studies concluded that high glycemic index and glycemic load have a modest yet significant proacnegenic effect, meaning they appear to nudge acne in the wrong direction, while calling for more randomized trials.

In practice, “low glycemic load” means swapping foods that spike blood sugar, like white bread, sugary drinks and fries, for whole grains, beans, vegetables and protein. The AAD’s diet page lists white bread, corn flakes, potato chips, fries, doughnuts, sugary drinks and white rice among the high-glycemic foods to watch.

Does milk or dairy cause acne?

There’s a consistent association, but it comes almost entirely from observational studies, which can’t prove cause and effect. A 2018 meta-analysis pooled 14 studies of 78,529 children, teens and young adults. Compared with low intake, people who drank more milk had higher odds of acne (odds ratio 1.28 for any milk and 1.32 for low-fat or skim milk). The authors warned that the results should be interpreted with caution due to heterogeneity and bias across studies.

The AAD’s patient page highlights one finding: women who drank 2 or more glasses of skim milk per day were 44% more likely to have acne. The 2022 systematic review found the dairy literature mixed, possibly depending on sex, ethnicity and dietary habits. One proposed explanation is that dairy raises insulin and IGF-1, a growth factor, as a 2024 review in Nutrients explains, and the 2022 systematic review notes that insulin, IGF-1 and androgens affect acnegenesis, the formation of acne. That’s a plausible mechanism, not proof.

If you want to test cutting back on milk, it’s low-risk for most adults, but dairy is a major source of calcium, so teens and parents should talk to a doctor or dietitian before cutting it out entirely.

Does chocolate cause acne?

Probably not much, if at all, but the question isn’t settled. A StatPearls review for clinicians says no substantial evidence supports the common assumption that chocolate exacerbates acne. The newer trials that suggest otherwise are very small and short:

• A double-blind trial gave 14 acne-prone men capsules containing unsweetened 100% cocoa, a gelatin placebo, or a mix of the two; among the 13 who finished, total lesions rose significantly at day 4 and day 7.
• A crossover trial in 54 college students found a milk chocolate bar produced an average of 4.8 more lesions after 48 hours, versus 0.7 fewer with jelly beans. The AFP summary noted unclear allocation concealment and no baseline severity data.

Chocolate bars also contain sugar and milk, so any effect may not come from cocoa at all. If chocolate reliably makes you break out, that’s worth noticing; there’s just no good reason to ban it for everyone.

Can whey protein cause acne?

Whey is a milk protein, so it’s under the same suspicion as dairy, and gym-goers often notice breakouts after starting shakes. The evidence is mostly case reports. One case series described six adolescent boys who developed acne on their trunk while taking whey supplements and improved after stopping them. That’s a useful signal but, with no comparison group, it can’t tell us how common the effect is. If you use whey and your acne worsened around when you started, a trial of a non-dairy protein is a reasonable experiment to discuss with your doctor.

Should you change your diet for acne?

Here’s where I land after reading the research: a diet change is a reasonable add-on, not a replacement for treatment.

• Start with proven treatments. Benzoyl peroxide and topical retinoids have much stronger evidence than any food change. My simple acne routine covers the basics.
• Try a low-glycemic swap first. It has the best trial evidence and is healthy anyway.
• Test one change at a time. The AAD suggests paying attention to whether any food or beverage seems to trigger a breakout. Give any change 10 to 12 weeks, the length of the diet trials, and remember acne naturally fluctuates. See how long acne treatments take for why patience matters.
• Don’t over-restrict. Cutting out whole food groups can backfire, especially for teens. If you’re cutting dairy, plan how you’ll get enough calcium.
• Adults with hormonal-pattern acne often need more than diet; my guide to hormonal acne in adults covers the options to discuss with a clinician.

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