A fat daytime sleepy person is like the obese character in Dickens and the illness has been called the Pickwickian Syndrome. Obesity in snoring men, but not in women, is predictive of sleep apnea. Nasal obstruction from a cold or hay fever makes it worse. Sedatives in women can do the same. Evening alcohol can convert a heavy snorer to sleep apnea.
Treatment includes avoidance of obesity and alcohol.
Good sleep habits and exercise help. Lying on one side also helps. A tennis ball sewn into a pajama pocket made between the shoulder blades area is helpful. Sometimes tricyclic antidepressants help. Some patients are not comfortable sleeping with a nasal mask.