We often think of sleep as “downtime,” but research shows it’s one of the most powerful regulators of appetite, metabolism, and long-term health.
A fascinating study from Columbia University found that people who slept just 4 hours per night ate an extra 300 calories per day compared to when they slept for 9 hours.
That might not sound like much—but over time, it adds up. That’s roughly 2 kg of body fat in six months, or 20 kg over five years if the habit continues. Most of those extra calories came from foods high in saturated fat, increasing both weight gain and cardiovascular risk.
How Sleep Loss Affects Eating
When you’re sleep-deprived, your hunger hormones fall out of balance:
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Ghrelin (“I’m hungry”) increases
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Leptin (“I’m full”) decreases
The result? Your brain keeps signalling for food—even when your body doesn’t actually need it.
In the Columbia study, women were more affected than men:
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Women ate an extra 329 calories per day
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Men ate an extra 263 calories per day
Over time, this difference can significantly impact body composition and long-term health.
The researchers followed 26 healthy men and women across:
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Six nights of short sleep (4 hours)
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Six nights of long sleep (9 hours)
Their conclusion: chronic short sleep predisposes people to weight gain, obesity, and higher cardiovascular risk.
What This Means for Shift Workers
For people working irregular hours or night shifts, this research hits close to home. Shift workers often experience disrupted sleep—and data shows they face higher risks of obesity, heart disease, and diabetes.
Practical strategies that help:
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Prioritise sleep – Aim for at least 7 hours per day. Use blackout curtains, eye masks, or white noise to improve quality.
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Pre-plan meals – Don’t leave food choices to late-night cravings. Pack balanced meals and snacks.
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Practice conscious eating – Ask: Am I truly hungry, or just tired, bored, or stressed? Try water, stretching, or a short walk first.
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Keep a routine – Even on days off, maintain a consistent sleep–wake schedule to stabilise appetite hormones.
The Bigger Picture
Poor sleep doesn’t just affect your waistline. It influences your:
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Metabolism
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Mood
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Immune system
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Heart health
Building better sleep habits may be just as important as diet and exercise when it comes to living longer, stronger, and healthier.
Think of sleep as your body’s reset button. Without enough of it, even the best eating and exercise habits lose their power.
The Bottom Line
If you’re trying to manage your weight, improve energy, or reduce disease risk, don’t overlook sleep. Protecting your rest is protecting your health.
Tonight, switch off the screens, dim the lights, and give your body the rest it deserves. Your future self will thank you.
References
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St-Onge MP, et al. Short sleep duration increases energy intakes but does not change energy expenditure in normal-weight individuals. Am J Clin Nutr. 2011.
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Spiegel K, Tasali E, et al. Sleep curtailment is associated with decreased leptin and elevated ghrelin. Ann Intern Med. 2004.
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American Heart Association. Short sleep duration and its impact on health.
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Australian Institute of Health and Welfare. Health impacts of shift work. AIHW, 2020.
