They may avoid some types of milk

People who don’t drink cow’s milk may be less likely to get acne than those who do, says dermatologist, Dr Joel Schlessinger.
A 2016 study of 225 teens aged 14 to 19 that was published in the Journal of the American Academy of Dermatology found that people who drank more low-fat or skim milk had more acne than people who did not drink as much. (The study included teens with moderate acne or no acne.) However, there was no link between acne and the consumption of dairy (in general) or full-fat milk. The authors note that the research on the topic has been mixed, and the study can’t determine if one factor caused the other. (It’s possible that skim milk is devoid of the good-for-your-skin fatty acids found in whole milk.) Some think it has to do with the high ratio of sugar found in skim milk. If you like it, you might consider trying almond milk. “Almond milk contains all of the great vitamins and calcium we need, but without any of the hormones,” Dr Schlesinger says.
They pass on the pasta

There may be less white bread, white pasta, white rice, potato chips, or other high glycaemic index (GI)-scoring carbs on the menu for the blemish-free. Instead, they may be more likely to eat foods that rank low on this index, such as multi-grain bread, peanuts, vegetables and beans. Emerging data suggest that high glycaemic index diets may be associated with acne, according to the latest guidelines from the American Academy of Dermatology. Exactly how a diet that is high on the GI index can cause or contribute to acne is not fully understood, but low GI foods keep blood sugar levels stable while high GI foods may cause a blood sugar spike that can lead to inflammation and oil production, which plays a role in acne. What’s more, eating lots of high GI foods can also increase hormones which in turn dial up the activity of oil glands in the skin, causing acne.
They wash their hands after working out

Sure, working out on a regular basis helps us stay fit and healthy, but if we don’t exercise caution with hand hygiene, we may break out – or worse, because gym equipment can be full of bacteria. “Working out in a gym is potentially very dirty and can cause something that looks just like acne, but is actually a staph infection,” says Dr Schlessinger. “The best thing to do is to avoid touching your face while playing sports or working out. If you must, bring a towel or use the back of your hand or sleeve.”