LONDON: Researchers found that people who slept less than seven hours were more likely to consume nearly 400 calories more the next day.
The research by King’s College London pooled data from 172 individuals in 11 separate studies to determine if sleep deprivation affected calorie intake, as reported in a Daily Mail article on Oct 24.
It found that when the participants slept less than the optimal seven hours a night, they ate an extra 385 calories the next day, which can increase the body weight by about half a kilogramme every week.
“If long-term sleep deprivation continues to result in an increased calorie intake of this magnitude, it may contribute to weight gain,” said Dr Gerda Pot, the study’s author and a lecturer in the Diabetes & Nutritional Sciences Division at King’s College London. “And ultimately to obesity and [being] overweight,” she said in a Huffington Post article.
While the sleep-deprived participants didn’t eat more, the researchers found that they tended to reach for food higher in fat content and lower in protein. This food-for-reward behaviour was the root of the additional calorie intake, said Dr Pot, as fat has more calories per gram than protein. Protein also keeps you fuller longer.
Staying up longer was another factor the researchers thought was contributing to the extra calories. “We simply have more hours to eat,” said Dr Pot in the Huffington Post story.
The body’s hormonal production is also affected when there is sleep deprivation. Ghrelin, a hormone that controls hunger, is higher, while leptin, which regulates energy and signals to the brain when you are full, is lower.
On average, the body needs to burn off an average of 3,500 calories per week (or 500 calories per day) to lose half a kilogramme. But being tired means people were less likely to be active, and this impacted their body's ability to burn calories and prevent weight gain, according to the study.
The researchers said it was important to pay attention to sleep habits as they can also affect the diet the next day.