Does sleeping too little make you gain weight? Science discovered the real reason
Sleeping Too Little Makes You Gain Weight (and It's Not Because of Hunger, As Everyone Thinks)
By Vanessa Manfredini | Biomedical Scientist and future Nutritionist
Do you sleep around 6 hours, feel "fine," and don't even consider yourself tired? 😴 Well, a study published this July put exactly that scenario to the test. And the result was surprising, especially the reason. Come with me! 🌿
"Poor sleep doesn't make you gain weight because it makes you hungry. It makes you gain weight because it steals your desire to move."
What scientists did 🔬
Researchers at Columbia University, in the United States, gathered 95 adults who usually slept 7 to 8 hours per night. For 6 weeks, they slept about 1 hour and 20 minutes less per night. Nothing extreme, mind you: it's exactly what many people experience in their daily hustle.
The result 📊
In just 6 weeks of sleeping a little less, participants:
📏 Increased waist circumference by about half a centimeter
🪑 Spent 17 more minutes per day sedentary
It might seem like a small amount, right? But stop thinking about 6 weeks and think about 6 months, 2 years, 10 years. This is how weight slowly increases throughout adult life, without us understanding where it came from. 🤯
The big surprise 🤔
Here's the game-changing finding. Everyone expected the explanation to be hunger, as it has always been said that poor sleep increases appetite. But that's not what happened.
Hunger hormones barely budged, and energy expenditure remained the same. What changed was behavior: people simply became more sedentary. Less energy, more couch time. And the detail is that they didn't compensate for this at any point during the day.
And here's the data that caught my attention 🌸
Among postmenopausal women (and also men), the effect was even greater: they spent almost 30 more minutes per day sedentary. That's almost double the general average.
What's more: the same research group had already observed that this same mild lack of sleep increased insulin resistance in women, with a stronger effect precisely after menopause. In other words, at this stage, sleep ceases to be "just rest" and becomes a central piece of health. 💚
What to do with this information 🌱
⏰ Gain 20 minutes at a time: no need to revolutionize your night. Moving bedtime up a little is already a start.
📱 Beware of "just one more episode": that's where the 80 minutes disappear.
🚶♀️ On bad sleep nights, move on purpose: now you know the tendency is to stay still without realizing it.
"Taking care of your sleep is one of the kindest ways to manage your weight."
Did you identify with this study? 💚
Tell me in the comments how many hours you've been sleeping. And share with that person who keeps saying "I sleep little and it's all good"! 🌹
With care and science, Vanessa 🌹
📚 Scientific References
Content based on recent research on sleep and weight. Main references:
- Zuraikat FM, et al. Prolonged Short Sleep and Its Effect on Body Weight and Composition: A Pooled Analysis of Randomized Trials. Annals of Internal Medicine, published online July 7, 2026. DOI: 10.7326/ANNALS-25-01660 (https://doi.org/10.7326/ANNALS-25-01660)
- Columbia University Irving Medical Center, dissemination material about the study conducted by Marie-Pierre St-Onge and collaborators.
- Previous studies by the same group on mild sleep restriction, insulin resistance in women, and markers of cardiac inflammation.
The information is for educational purposes and does not replace consultation with health professionals. Study results represent group averages and may not apply to every individual. Science is constantly evolving.