Insufficient sleep may contribute to weight gain and make it harder to lose excess body fat, even among people who maintain a healthy diet and exercise regularly, according to Dr Manal Nasr, Family Medicine specialist at Al Waab Health Centre, affiliated with the Primary Health Care Corporation (PHCC).
Dr Nasr said numerous scientific studies have highlighted the relationship between inadequate sleep, increased appetite, irregular eating patterns and weight gain, stressing that sleep is an important, but often overlooked, factor in maintaining a healthy weight.
At first glance, the link between sleep and weight may not appear obvious. However, insufficient or irregular sleep can affect appetite, metabolism and eating behaviour by altering the hormones responsible for hunger, satiety and energy regulation.
Sleep is a vital physiological process that helps regulate numerous bodily functions, including the secretion and activity of hormones involved in appetite, satiety, metabolism and energy balance. When people regularly stay up late or sleep fewer hours than their bodies require, changes may occur in the hunger and satiety signals regulated by hormones such as ghrelin, leptin, and insulin.
Ghrelin and leptin have opposing effects on appetite. Ghrelin stimulates hunger, while leptin promotes feelings of satiety. Insulin, meanwhile, plays an important role in regulating blood glucose levels and fat storage. Dr Nasr explained that leptin levels normally increase during the night when a person gets sufficient sleep, reaching their highest levels in the early morning. This gradual increase helps suppress hunger.
When the body does not get enough sleep, leptin levels may remain low, causing the nervous system to perceive that the body needs more energy. This can trigger hunger signals and increase the desire to eat, potentially leading to excessive calorie consumption and the storage of surplus energy as body fat.
Ghrelin, on the other hand, is the hormone that stimulates hunger and normally decreases during sleep as the body rests and its energy requirements decline. Insufficient sleep can interfere with this normal decline, resulting in persistent feelings of hunger and stronger cravings, particularly for high-calorie foods.
Dr Nasr added that insulin plays an important role in both blood glucose regulation and fat storage. Studies have shown that insufficient sleep may reduce the body's sensitivity to insulin, a condition known as insulin resistance, which can contribute to weight gain and the accumulation of body fat.
She noted that insufficient sleep may therefore affect the balance and function of hormones involved in appetite and metabolism, potentially creating conditions that favour increased food intake and fat accumulation. Scientific studies have also found an association between shorter sleep duration and a higher body mass index (BMI), as well as an increased risk of conditions such as diabetes and high blood pressure.
Staying awake for longer hours also creates additional opportunities to eat, particularly late at night. Such meals and snacks may be high in calories, sugar and fat. At the same time, insufficient sleep can cause daytime fatigue and lower energy levels, reducing a person's motivation to exercise or engage in normal daily activities. Over time, the combination of increased calorie intake and reduced energy expenditure can contribute to weight gain.
However, Dr Nasr stressed that multiple factors, including diet, physical activity, age, genetics and overall health, influence weight gain. Healthy sleep should therefore be considered an important part of a balanced lifestyle and weight-management strategy.
Addressing weight gain should not be limited to asking what a person eats, but should also include questions about sleep patterns and daily routines. Sleep is not a luxury but an essential component of a healthy lifestyle, Dr Nasr said, noting that adequate and regular sleep can support healthy weight management and overall quality of life.
She recommended maintaining consistent sleep and wake-up times as much as possible and getting an adequate amount of sleep appropriate for each age group.
With the start of the new academic year, establishing healthy sleep routines is particularly important for children and adolescents. Regular sleep can help improve concentration and daytime energy. Families should gradually adjust bedtime and wake-up times before the start of the school year and maintain consistent schedules as much as possible. Staying up late and using phones and other electronic devices before bedtime should be avoided, while heavy meals, sweets and high-calorie beverages at night should be limited.
Regular physical activity should also be maintained to promote better sleep quality and support a healthy lifestyle overall.