There is no such thing as soda that is good for you, anything with preservatives and an array of chemicals is not good for you in the slightest. Our bodies are of the Earth and should be fed and watered with things of the Earth, not man made substances.
Brysing gives the best advice, of course hormones play a part, but the average teenagers diet is shockingly bad. I found that swapping all drinks for either water or tea barring when I go out with friends once or twice a week, made my skin a lot better. It gave good hydration to the cells, and I not only looked better but felt better mentally too.
As for natural methods, tea tree oil is one of the best things for your skin so long as you dilute it, some like to dab it on to a spot with a cue tip only touching that area. This is good, but not everyday as it can make your skin dry. Another method would be to dilute some in a basin of water to wash your face.
After washing your face you could apply witchhazel astringent to the skin using cotton wool, this will balance the oiliness of the skin and close the pores preventing further breakouts.
Sugar is bad for the skin, as are bad fats (saturated). But something most people overlook is dairy, most people's body simply doesn't handle dairy very well and dairy can cause skin issues. I am not the only one who gets breakouts when I consume dairy, and I have noticed it also irritates my eczema, even just a couple of spoonfuls of yoghurt.
Honestly, it's all abut knowing what is good for your body and yourself, and the only way you will know that is through applying basic nutritional information and trial and error.