Does diet cause acne? What dairy and sugar do

Most people who ask whether food causes acne want a yes or a no. The research gives a narrower answer. A few foods are linked to more acne in studies, mainly cow's milk and foods that raise blood sugar fast. Most of those studies are small or rely on people remembering what they ate, and the main guideline groups read them in different ways. This guide sets out what each source says, food by food, so you can decide what to test on your own skin.

What the main guidelines say about diet

Three sources shape most medical advice on acne and food, and they give different weight to the same research.

The American Academy of Dermatology (AAD) is the main professional group for skin doctors in the United States. Its public page on diet and acne says small studies suggest a low-glycemic diet may reduce acne, and that some studies link cow's milk to more breakouts. The same page says other studies found no link between a high-glycemic diet and acne, and that more research is needed to know for sure.

NICE, the body that writes health guidance for England, is more careful. Its acne guideline, NG198, tells doctors to advise people "that there is not enough evidence to support specific diets for treating acne." The committee behind it reviewed a small number of trials of a low-glycemic diet and found some evidence of benefit. It still chose not to recommend any diet. Part of its reason was that weight loss and close attention to food raised concerns about eating disorders. Most people with acne are young, and the guideline points out that eating disorders most often start in the teenage years.

The NHS acne page lists these causes: changes in hormone levels, conditions such as PMOS and rosacea, some medicines, and products on your skin or hair that make it greasy. The list names no food or drink.

Foods that raise blood sugar fast

The glycemic index is a score for how fast a food raises the sugar in your blood. A high-glycemic food raises it fast. A low-glycemic food raises it slowly.

The AAD gives these examples of high-glycemic foods and drinks: white bread, corn flakes, puffed rice, potato chips, white potatoes or fries, doughnuts and other pastries, sugary drinks such as milkshakes, and white rice. Its examples of low-glycemic foods are most fresh vegetables, some fresh fruits, beans and steel-cut oats.

The studies the AAD describes are small:

Where	Who	What happened
Australia	43 males aged 15 to 25, for 12 weeks	Those on a low-glycemic diet had less acne than those on their normal diet
Korea	32 people aged 20 to 27, for 10 weeks	Those on a low-glycemic diet had less acne at the end
USA	2,258 people on a weight loss diet	87 percent said they had less acne, and 91 percent said they needed less acne medicine
Turkey	86 people who kept a 7-day food log	Those with the most severe acne ate a high-glycemic diet

The USA figures are what patients said about their own skin, and that diet was meant for weight loss. Only the Australian and Korean studies compared a low-glycemic diet with a normal diet over several weeks.

Why might blood sugar matter? The AAD describes what scientists believe. A fast rise in blood sugar causes inflammation in the body, and it makes the skin produce more sebum, the oily substance in your skin. Both inflammation and extra sebum can lead to acne. The AAD presents this as a belief that still needs more research.

Sugar and greasy food

Sugary foods are part of the same research. Sugary drinks and pastries are on the AAD's high-glycemic list.

A French study of 24,452 adults, published in JAMA Dermatology in 2020, looked at diet and acne in grown adults. It found current acne was linked to eating fatty and sugary products, to sugary drinks and to milk. The study measured diet and acne over the same period. Its authors describe the result as an association and call for larger studies.

Greasy food gets a specific comment from the AAD. Its diet article opens with greasy fries and burgers and says there may be a connection, with a different reason from the one most people expect. Fries and potato chips sit on its list of foods that raise blood sugar fast. The AAD links fries to acne through their effect on blood sugar.

Grease on the skin is a separate matter. The NHS names products on your skin or hair that make your skin greasy as one cause of acne.

Cow's milk, skim milk and other dairy

Milk has more research behind a link to acne than any other food. The AAD says cow's milk is a low-glycemic drink (milkshakes are the exception), yet some studies link it to more breakouts. All types of cow's milk, whole, low-fat and skim, have been linked.

The best known study asked 47,355 adult women in the United States to recall what they ate in high school. Women who drank 2 or more glasses of skim milk a day were 44 percent more likely to have acne than the others. Two later studies by the same research group followed 6,094 girls and 4,273 boys aged 9 to 15, with two long diet questionnaires at least a year apart. The girls who drank the most cow's milk of any type were more likely to have acne. The boys who drank skim milk were more likely to have acne.

A 2021 review in the American Journal of Clinical Dermatology lists the limits of these studies. The study of 47,355 women relied on people remembering their diet from at least ten years earlier, and dairy took up 2 of the 22 questions. The studies of girls and boys were based on questionnaires, with no blinded measurement of anyone's skin. The review also calls the link between skim milk and acne in boys weak.

Yogurt and cheese give a different result. The AAD says no studies have found that products made from milk, such as yogurt or cheese, lead to more breakouts.

Why might milk matter? The AAD says the reason is still unclear. It names one theory: some of the hormones in milk may cause inflammation inside the body, and inflammation can clog pores. It adds that more research is needed.

Chocolate

Chocolate has two small trials, both in men.

In a 2014 trial, 14 men aged 18 to 35 with a history of acne took capsules of unsweetened 100 percent cocoa, gelatin powder, or a mix of both. Thirteen finished. Their total acne spots rose on day 4 and day 7 compared with the start. In a 2016 trial in Thailand, 25 men with acne-prone skin ate 25 grams of 99 percent dark chocolate every day for 4 weeks. Their acne scores and their counts of blackheads, whiteheads and inflamed spots rose from week 2 and stayed higher at week 4.

The 2021 review lists two limits of the cocoa trial: it used one brand of chocolate, and it included no women. The review adds that where studies link chocolate and sweets to acne, the cause is unclear. It could be the sugar in these foods, or people with acne could be eating more sweets.

Whey protein shakes

Whey is one of the two main proteins in cow's milk. It is the main ingredient in many protein powders sold for exercise. The studies on whey and acne disagree.

A 2024 study from Jordan compared 100 young men with acne and 101 without, all of them going to gyms. In the acne group, 47 percent had taken whey protein supplements in the past three months, against 27.7 percent of the group without acne. The authors describe this as an association.

A 2024 trial from Thailand tested whey directly. Forty-nine young men with mild to moderate acne took either 30 grams of whey a day or a supplement without whey, for 6 months. The whey group's acne counts and severity were no worse than the other group's, within the limit the study set in advance.

Earlier reports describe single cases. In one case series cited by the 2021 review, five boys aged 14 to 18 got acne after starting whey supplements, and standard acne treatment worked poorly for them. Four stopped taking whey, and their acne cleared. Reports like these describe a few people and cannot say how common the effect is.

If your acne started around the time you began a protein supplement, tell your doctor.

How to test a food on your own skin

The AAD's advice for right now is practical. Dermatologists recommend that you watch your breakouts and ask two questions. Does any food or drink seem to trigger a breakout or make your acne worse? If something seems to, what happens when you go without it for a day, a week or a month?

A food diary makes those questions easier to answer. The Turkish study in the table above used one, a 7-day food log. For your own test, write down what you eat and drink each day, and take a photo of your skin at the same time and in the same light. How to take acne progress photos that actually show change explains how to set up the photo so two weeks can be compared side by side, and the progress tracker keeps your photos in order by date.

Change one thing at a time. If you drop a daily glass of skim milk and start a new cleanser in the same week, you cannot tell which change helped. Keep your acne routine the same while you test a food.

Test a single item, such as one daily drink or one supplement. Removing a whole food group, such as all dairy, is a bigger change, and it is one to plan with a doctor or a registered dietitian. The NICE committee chose not to recommend acne diets partly because close attention to food can lead to eating disorders in young people. If worry about food starts to take over your day, talk to a doctor.

Hormones can cause a pattern that looks like a food reaction. Acne that flares in the same week of each menstrual cycle has its own guide: hormonal acne vs regular acne.

Diet works alongside treatment

The AAD is direct on this point. Keeping your skin clear requires more than a diet change, and acne-friendly skin care and acne medicine help prevent new breakouts. A food change that helps you adds to a routine.

The complete acne skincare routine covers each step, the ingredient strengths and how long to wait before you judge a treatment. To choose a first treatment, see salicylic acid vs benzoyl peroxide. For a routine built from a photo of your own skin, analyze your skin.

The NHS says to see a GP if you have tried treating acne yourself and it is not getting better, if you have many spots or the spots are deep, painful or causing scars, or if acne is affecting your mental health. Those reasons apply whatever you eat.