There is no direct connection between eating greasy hamburgers and chocolate or drinking excessive soft drinks and developing spots. It is the case however that what we eat plays a role in the way the body functions and so it does have a small role to play in whether acne is less or more likely.
For example, greasy foods do not directly turn into increased oil production from the sebaceous glands which adds to acne, but foods which do increase the oil production would of course have an effect. However, iodized salt is as yet the only food which has been shown to have any real effect and it just worsens acne but does not cause it.
Hygiene
The odds of developing a pimple are increased when a pore gets plugged and bacteria get trapped inside. This means that hygiene habits which tend to close the pores can play a role. However this effect is only small and the bacteria and dead cell skins which become trapped and are unable to work their way out of the pore are influenced only to a small degree by insufficient regular face washing.
Nevertheless, after acne occurs good skin hygiene is especially important and mild cleansing two times a day with soap and water can help in treating acne and encouraging healthy skin in general. Cleanliness is an excellent for several reasons although it is most helpful in treating acne by providing a good surface allowing medications to do their work most effectively.
Acne spots are greatly influenced by excess skin oil (sebum) production which is triggered chiefly by hormones and abrasive cleansers which are applied roughly do not only clear away this excess oil but also weakens the skin's ability to cope with it.
Stress
As stress tends to weaken the body's immune system and also influence its hormone levels it could be thought that stress would play a role in the onset of acne. However, there is no evidence to suggest that stress leads to acne, although there is some evidence to show that it might play a small role after acne has arrived.
One difficulty with assessing the role played by stress is that people who suffer from chronic stress normally also suffer from additional health problems which complicate the picture. Do not forget also that here we are talking about clinical stress and not just the worries which we all experience as part of the ups and downs of day to day life.
Medications
Many us are tempted to raise the dosage of an over-the-counter medication believing that if a little can do a bit of good a lot of medicine will do a lot of good. Unhappily, this is not so and it is both a waste of medication and could actually harm the skin. You should always follow the instructions on any medication and if an over-the-counter medication is not showing signs of working within a reasonable period of time then it is a good idea to consult a dermatologist.