"Cut out sugar and your skin will clear up." It's one of the most repeated pieces of skincare advice online, and like most oversimplified advice, it contains a grain of truth wrapped in an overstatement.
What the Actual Link Looks Like
Research has found associations between high-glycemic diets, sugar and refined carbohydrates that spike blood sugar quickly, and increased acne severity in some people. Dairy has shown a similar pattern in some studies, particularly skim milk. These are real, documented associations. They are not the same as "diet causes acne" or "cutting dairy will clear your skin."
The relationship is more like a contributing factor than a root cause. Someone with a stable skin barrier and no other acne triggers might eat a high-sugar diet with minimal skin impact. Someone with a compromised barrier or hormonal factors already driving breakouts might notice diet has more visible influence, layered on top of causes that have nothing to do with food.
Why Diet-Only Approaches Usually Disappoint
People who overhaul their diet expecting clear skin and don't get it often conclude diet doesn't matter at all, when the more accurate conclusion is usually that diet was one factor among several, and the others went unaddressed. Skin barrier condition, hormonal patterns, and skincare routine itself typically matter more than diet alone, which is why a diet change by itself rarely resolves acne that has other drivers still in play.
A More Useful Way to Think About It
Diet is worth paying attention to if you notice a clear personal pattern, breakouts that reliably follow specific foods. It's not worth treating as the primary lever if your acne has other, more obvious triggers, like an aggressive skincare routine or an unaddressed barrier issue. Fixing the skin-level causes first, then observing whether diet still moves the needle, tends to be more useful than assuming diet is the answer from the start.