Why do people snorw and make noises when there asleep? is it cause there fat?

Snoring sounds: Snoring is the noise produced by vibration of the upper airway walls as a result of partial upper airway obstruction during sleep. It can be caused by a spectrum of sleep-disordered breathing disorders, ranging from intermittent simple snoring to chronic heavy simple snoring, upper airway resistance syndrome and obstructive sleep apnea-hypopnea. (quoted from epocrates).Fat can make it worse.