The doctor first pointed out, as we have discussed, that weight gain contributed to obstructive sleep apnea by placing additional weight on the airway during sleep. However, he also noted that being overweight affects the nerve signals from the brain to the airway. The result is that the muscles in the airway lose tone and become flaccid, which makes them less able to keep the airway open, especially when relaxed during sleep. Interestingly, no one knows why the signals change. Some point to the hormone leptin (you can read more about the correlation between sleep apnea and leptin levels in this blog), saying that too much leptin could affect breathing control.
Because of this twofold contribution of being overweight to sleep apnea, it certainly seems that weight loss as part of a comprehensive program of behavioral therapy is a good first step. At the very least, losing weight will probably reduce the volume and frequency of snoring, and it may reduce severe sleep apnea to a moderate level that can be controlled with oral appliance therapy as opposed to the less convenient CPAP.