Sleep and cravings
One short night makes tomorrow's fast twice as hard.
Key points
- Sleeping under 7 hours raises ghrelin (hunger) and lowers leptin (fullness). People eat around 250–400 extra calories the next day, mostly snacks.
- Late-night eating pushes your body clock and worsens sleep quality — finishing dinner 3 hours before bed helps both sleep and fasting.
- Fasting itself can disturb sleep at first; magnesium at night, less caffeine and a cool, dark room usually fix it.
- An early eating window (e.g. 8am–4pm) improves insulin sensitivity more than a late one — but the best window is the one you'll stick to.
Spiegel et al., Ann Intern Med 2004; Nedeltcheva et al., Am J Clin Nutr 2009; Sutton et al., Cell Metab 2018.
Hunger Wave provides general educational information based on published research. It is not medical advice and does not replace a consultation with a healthcare professional. Stop fasting and seek help if you feel unwell.
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