New Delhi: People who stay up late and consume energy-dense foods at night may be at a higher risk of obesity, increased belly fat and poorer blood sugar and cholesterol levels, according to a new study published in the journal Frontiers in Nutrition.
Researchers found that while “night owls” and “early birds” consumed similar amounts of food over an entire day, the timing of meals played a significant role in influencing body composition and metabolic health. The findings suggest that reducing late-night eating could help improve health outcomes, particularly among individuals who naturally prefer staying awake until late.
Meal timing matters as much as diet
The study was led by Rozanne Kruger from Griffith University’s School of Allied Health, Sport and Social Work.
According to Kruger, a person’s chronotype—the natural preference for sleeping and waking early or late—can influence eating habits, metabolism and overall health.
“Chronotypes influence our preferences for food intake, our behaviours and our metabolism,” she said.
The researchers observed that although morning and evening chronotypes consumed nearly the same total daily energy, the time at which they ate differed considerably.
Study examined women aged 18 to 45
The research involved 287 European and Pacific New Zealand women aged between 18 and 45 years.
Participants were categorised into:
- Morning chronotypes (early birds)
- Intermediate chronotypes
- Evening chronotypes (night owls)
Researchers analysed participants’ dietary habits, meal timing and body composition to understand how eating patterns affected health.
Night owls consumed more calories late in the day
The study found that evening chronotypes consumed relatively little food between 3 am and 9.59 am, but significantly increased their food intake between 8 pm and 2.59 am.
In contrast, morning chronotypes consumed more of their daily calories earlier in the day and less at night.
Night owls were also more likely to:
- Skip or eat lighter breakfasts.
- Consume lower amounts of protein in the morning.
- Eat foods rich in carbohydrates and fats late at night.
- Choose meals with lower micronutrient density.
Researchers noted that evening chronotypes generally consumed less nutrient-rich food than morning and intermediate chronotypes.
Greater risk of obesity and metabolic disorders
The study found that higher calorie and macronutrient intake during the evening was associated with:
- Higher body fat percentage.
- Increased abdominal (belly) fat.
- Poorer cholesterol and lipid profiles.
- Less favourable blood sugar regulation.
Researchers suggested that eating during the body’s natural resting period may increase the tendency to store energy as fat instead of using it efficiently.
According to the study, this could make evening chronotypes more susceptible to obesity and related metabolic conditions.
Why eating late may be harmful
The authors explained that the human body is biologically programmed to fast and rest during the night.
Consuming large meals late in the evening may disrupt normal metabolism and increase fat storage, potentially leading to long-term health problems.
The findings reinforce growing evidence that meal timing is an important component of maintaining good metabolic health.
Researchers recommend limiting late-night meals
The researchers concluded that improving meal timing may be an effective strategy for individuals who naturally stay awake late.
“The research highlights that when people eat may be just as important as what they eat,” Kruger said.
She added that reducing late-night eating could help lower obesity risk and improve metabolic health among people with an evening chronotype.
While the study establishes an association between late-night eating and poorer health indicators, it does not prove that meal timing alone causes obesity. The researchers said further studies involving larger and more diverse populations would help strengthen understanding of the relationship.
