Stay up late? You are probably eating late, too.
A new study finds this isn’t just a habit. It’s a biological trap for obesity. Specifically for women in New Zealand with European and Pacific ancestry, staying up late links to worse metabolic health. The reason? They eat most of their calories after the sun goes down.
Chronotype is what you call it. The preference for when to sleep. Wake up early? You’re a morning person. Stay up late? You’re an evening person.
Professor Rozanne Kruger from Massey and Griffith universities knows the deal. She notes these timings modulate physiology and behavior.
“Chronotypes influence our preferences for food inta ke, our behaviors and our metabolism.”
The research tracked 287 women. Healthy ones. They kept five-day food diaries. Scanned their bodies via X-ray for composition. Gave blood.
Half were “intermediate” sleepers. Thirty-four percent were night owls. Twelve percent early birds.
The night owls had it worse.
Average BMI hit 31.4. Morning and intermediate types sat at 26.1. Night owls carried more total body fat. More belly fat. Specifically a higher android-to-gynaid fat ratio. That’s abdominal storage. Bad for heart health.
Here is the kicker. Total calorie counts didn’t vary much. The timing did.
Morning people ate before 10 AM. Night owls ate after 8 PM.
The pattern got worse with higher body fat. Heavier night owls skipped breakfast. Then they gorged on carbs and fat late at night.
Quality suffered, too. Evening types got less fiber. Less vitamin A and E. Less folate, calcium, magnesium. Their diets were poorer. Yet they consumed slightly more energy overall.
Blood tests told the grim story.
Triglycerides up. Insulin up. Glycated hemoglobin up. Leptin up. HDL “good” cholesterol down. Ghrelin appetite hormone down.
It is not just correlation.
Greater morning intake linked to better cholesterol and insulin control. Greater evening intake linked to higher blood sugar and lipids.
“Consuming food at night means we store more food rather use it.”
Storage becomes obesity. Obesity brings sickness.
The paper landed July 7, 2036 in Frontiers in Nutrition. The authors are Carlien van der Merwe and colleagues.
They argue fasting at night is key. If you eat then, you bypass burning fat. You just pile it on.
So maybe put the plate down earlier?
Or just accept that the clock wins.
