Sleep Loss and Hunger Hormones: The Ghrelin-Leptin Disruption

If you’ve ever craved junk food after a poor night’s sleep, there’s a biological reason — sleep deprivation severely disrupts your appetite-regulating hormones. In particular, it lowers leptin (the satiety hormone) and increases ghrelin (the hunger hormone), setting you up to overeat.

A major study found that people sleeping just 5 hours per night had 15% lower leptin and 15% higher ghrelin than those getting 8 hours [PLOS Medicine]. These shifts not only make you feel hungrier but also increase cravings, especially for high-calorie, high-carb foods — contributing to weight gain and metabolic stress.

Sleep loss doesn’t stop at leptin and ghrelin. It also raises evening cortisol (your stress hormone), which promotes fat storage, particularly around the abdomen, and can lead to insulin resistance over time. Combined, these hormone changes create a perfect storm for weight gain, increased blood sugar, and a reduced ability to self-regulate intake.

Chronic sleep restriction has been strongly linked to obesity, especially in populations who average fewer than 6 hours per night. The effects are also seen in children, shift workers, and individuals with sleep disorders like insomnia or sleep apnea.

💡 Practical Takeaways:

• Prioritise 7–9 Hours: Hormonal balance and appetite regulation depend on adequate sleep duration.
• Set a Routine: Going to bed and waking up at consistent times stabilises leptin and ghrelin rhythms.
• Limit Blue Light: Exposure to screens before bed suppresses melatonin, delaying sleep and worsening hormonal disruption.
• Avoid Sleep Debt: “Catching up” on weekends doesn’t fully reset metabolic hormone changes caused by chronic restriction.
• Address Sleep Disorders: Conditions like apnea or insomnia may require clinical intervention to restore hormonal balance.

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