Overweight people tend to have sleep apnea and snoring with hormonal imbalances
The hormone connection
Most people have heard the suggestion that if you want to stop snoring, then lose weight. But have you considered that a better night’s sleep could actually help you lose weight? Snoring and obstructive sleep apnea (OSA) are common with the overweight population. The connection between sleep disorders and weight is largely determined by two particular hormones ghrelin and leptin.
How it works
Leptin is an adipocyte-derived (fat cell) hormone that suppresses appetite. After calories have been consumed and the body is at its proper weight the fat cells themselves excrete leptin which tells the brain that no more food is required. This works well for persons of average weight. However obese individuals (who tend to have sleep breathing disorders) suffer from Leptin resistance. For the overweight, their fat cells constantly excrete high levels of leptin (“saying don’t eat”) but the brain cannot process the message. More and more leptin is produced, but because of this leptin resistance the body continues to think it needs to eat more and does. However, better sleep improves leptin resistance. Reducing fructose consumption helps too.
Ghrelin is predominantly a stomach-derived peptide hormone that stimulates hunger and food intake – appetite. High levels of ghrelin make you hungry. Overweight people and those suffering from OSA have high levels of ghrelin. OSA seems to make the ghrelin higher. Treating sleep apnea reduces ghrelin.
So overweight people with sleep breathing disorders (OSA and snoring) likely suffer from leptin resistance and high ghrelin levels causing them to always be hungry and eat more particularly high energy dense foods such as fructose and other carbohydrates. It appears that a sleepy brain appears to crave junk food while also lacking the impulse control to say no (leptin resistance).
The brain is always telling the overweight person that they are hungry because of the imbalance of these hormones.
Weight is reduced if sleep apnea and snoring are treated
The hormone balance is improved when the sleep apnea and snoring are treated resulting in weight loss. ,  Leptin resistance is known to significantly improve and ghrelin is reduced when sleep apnea is treated. Poor quality sleep is associated with increase weight gain and subsequent sleep breathing disorders. 
CPAP and Snoring Mouthpieces
A major sleep study treating obstructive sleep apnea in obese patients by using CPAP and mandibular advancement appliances (snoring mouthpieces) like the SleepTight Mouthpiece showed significant improvement in the leptin and ghrelin hormone levels as well as weight reduction . As these patients received improvement in their hormone levels their sleep apnea improved and their weight gain was reduced.
CPAP SleepTight Mouthpiece
Proper medical advice is recommended. But is should be noted that diet modification particularly the reduction of fructose consumption and improving your sleep hygiene as well as the incorporation of easy to use oral appliances such as the SleepTight Mouthpiece may help with weight loss too.
Obstructive sleep apnoea syndrome (OSAS) is a common disorder in obesity. Leptin, an adipocyte-derived signalling factor, plays an important role in metabolic control. There is growing evidence that leptin regulation is altered in OSAS. Therefore, the aim of this study was to test the hypothesis that effective treatment will influence leptin levels in OSAS patients. Serum leptin levels were determined in 86 consecutive patients (aged 57.5 +/- 11.0 yrs) with polysomnographically verified OSAS. In addition, leptin levels were reassessed and treatment efficacy was evaluated by polysomnography after 6 months of therapy. Patients were treated with continuous or bilevel positive airway pressure, a mandibular advancement device or conservatively, depending on the clinical symptoms. Mean serum leptin levels did not change with treatment in the whole study group (7.3 +/- 5.0 versus 7.5 +/- 4.8 ng.mL-1), however, leptin levels decreased in effectively treated patients (8.5 +/- 5.0 versus 7.4 +/- 5.1 ng.mL-1) while they increased in ineffectively treated patients (5.0 +/- 4.0 versus 7.7 +/- 4.1 ng.mL-1). Furthermore, not only was there a significant and independent correlation between the change in leptin levels with treatment and the change in body mass index, but also with the change in apnoea/hypopnoea index. Effective treatment of sleep-disordered breathing may have significant effects on leptin levels in obstructive sleep apnoea syndrome patients. Changes in leptin levels are related to changes in apnoea/hypopnoea index in obstructive sleep apnoea syndrome patients.
Treatment of OSAS, for example with CPAP or with a mandibular advancement device, can normalise breathing during the night and reduce leptin levels [7, 8, 18]. The present study indicates that changes in leptin levels are related to changes in BMI and in AHI. In support of this finding, the study of CHIN et al.  indicated that the correction of breathing by CPAP [or mandibular advancement device] reduced visceral fat. The results of the present study show that the decrease of leptin levels is highest in patients with a large reduction in AHI.