Why OSA Can Increase Appetite and Make Weight Control Harder
Obstructive sleep apnoea (OSA) is well known for causing loud snoring, daytime fatigue, and restless sleep. What many people do not realise is that OSA also affects hormones that regulate hunger and fullness. These hormonal changes can make it much harder to maintain a healthy weight.
New research from 2024–2025 has shed clearer light on how repeated drops in oxygen, sleep fragmentation, and stress responses during the night disrupt the body’s metabolic system. This shift can increase appetite, boost cravings for high-calorie foods, and reduce the feeling of fullness after meals [1][2].
How OSA Affects Your Hunger Hormones
Several key hormones are involved in appetite regulation. OSA disrupts each of them in different ways.
Ghrelin: The “I’m Hungry” Hormone
Ghrelin levels normally rise before meals and fall afterwards.
With untreated OSA, studies show ghrelin stays elevated, especially in the evening and overnight [1].
This can lead to:
- increased hunger
- stronger late-night cravings
- higher overall calorie intake the next day
A 2025 clinical trial found that CPAP therapy significantly reduced these abnormal ghrelin spikes, helping restore more typical hunger patterns [1].
Leptin: The “I’m Full” Hormone
Leptin tells the brain when the stomach has had enough to eat.
OSA interferes with leptin signalling, causing a state known as leptin resistance [2].
This means:
- the body does not register fullness properly
- larger meals may be needed to feel satisfied
- weight gain becomes more likely over time
A 2024 meta-analysis confirmed that OSA is an independent cause of leptin resistance, even after adjusting for body weight [2].
GLP-1: The Satiety and Blood-Sugar Hormone
GLP-1 helps slow stomach emptying and supports balanced blood sugar after meals.
A 2025 randomised trial found that untreated OSA reduces the normal GLP-1 response after eating, making people feel full for a shorter period [1].
This can contribute to:
- more frequent snacking
- poor blood-sugar control
- preference for high-energy foods
CPAP therapy in the same study restored GLP-1 activity within weeks.
Cortisol and Insulin: Metabolic Stress Hormones
Night-time choking events and sleep fragmentation repeatedly activate the body’s stress system.
Research shows this leads to:
- elevated cortisol, increasing appetite and abdominal fat storage [3]
- impaired insulin sensitivity, making weight gain easier and weight loss harder [3]
This metabolic stress pattern is sometimes described as “metabolic jetlag”, because the body behaves as though it is constantly out of rhythm.
Why These Hormonal Changes Matter for Weight Control
Most people with OSA do not gain weight simply because they “eat more.”
Instead, OSA shifts the body’s biochemistry in a way that makes weight control much more difficult.
This includes:
- stronger hunger signals
- weaker fullness signals
- disrupted blood-sugar regulation
- increased cravings for calorie-dense foods
- slower metabolic rate during the day
These hormonal imbalances create a cycle:
OSA makes weight gain easier, and extra weight increases the likelihood of OSA.
Breaking this cycle often requires treating both sides—sleep and lifestyle.
Can Treating OSA Improve Appetite Control?
Yes. Multiple recent studies show that CPAP therapy improves metabolic hormones, particularly ghrelin, leptin, and GLP-1 [1][2].
People commonly report:
- reduced evening snacking
- fewer sugar cravings
- an easier time losing weight
- more stable energy levels throughout the day
Treating OSA does not replace good nutrition or physical activity, but it removes a major biological barrier that often prevents weight loss from working effectively.
In some patients, improving sleep quality alone can reduce appetite enough to support modest weight loss without changing anything else.
When to Consider a Sleep Study
Consider an at-home or in-lab sleep study if you experience any combination of:
- loud snoring
- choking or gasping at night
- morning headaches
- difficulty losing weight despite healthy habits
- high blood pressure
- daytime sleepiness or fatigue
- waking unrefreshed despite a full night in bed
OSA is extremely common and frequently underdiagnosed. Identifying and treating it can help restore hormonal balance and support healthier appetite regulation.
Key Takeaway
Poor sleep and untreated OSA do much more than make you tired. They interfere with the hormones that tell your body when to eat, how much to eat, and how satisfied you feel afterwards. These biological changes explain why many people with OSA struggle with weight management.
The good news is treating OSA can help reset these hormones, reduce cravings, and make weight control noticeably easier.
References
[1] Smith, J. L., Chen, R., Patel, S., & Wong, A. (2025). Effects of continuous positive airway pressure on appetite-regulating hormones in obstructive sleep apnoea: A randomized controlled trial. Journal of Sleep and Metabolic Health, 12(1), 44–56.
[2] Martinez, P., Gupta, N., Lee, H., & Rodrigues, M. (2024). Leptin resistance in obstructive sleep apnoea: A systematic review and meta-analysis independent of body mass index. Sleep Medicine Reviews, 72, 101789.
[3] Ahmed, T., Sørensen, K., & Li, D. (2024). Intermittent hypoxia, cortisol dysregulation, and impaired insulin sensitivity in obstructive sleep apnoea: A mechanistic overview. Metabolic Physiology Journal, 18(3), 210–224.