This article was updated Nocember 2025.
The impact of sleep on our physical well-being is significant. Apart from being crucial for the development and restoration of our muscles and cells across our body, it also bolsters our immune system and enhances our capacity to combat infections. Intriguingly, sleep aids in sustaining a balance among hormones that control our appetite and satiety signals in relation to food. This balance can be disrupted by inadequate sleep, which is associated with a higher risk of obesity in the long run. With up to 10% of Australians reported as suffering from insomnia, and obesity rates ever climbing, focusing on improving sleep patterns is a crucial, yet often overlooked part of overall health. So how does a lack of sleep relate to poor dietary habits and weight issues?
Studies show lack of sleep is linked to poor diet and obesity
A large Australian study conducted by a team of researchers from Monash University assessed the sleep behaviours and food choices of more than 7,000 Australian women aged 31-36 years. According to Dr. Michelle Blumfield, who lead the research team, sleeping difficulties were linked with heavier body weight, and poorer mental and physical health, as perceived by the study participants.
Dr. Blumfield, an Accredited Practising Dietitian, explained that the research showed lack of sleep can lead to poorer dietary choices in women of childbearing age, which can impact the health of their children. Improving sleep patterns may assist women to optimise their dietary intake in preparation for pregnancy. One in three Australian women are overweight or obese at the beginning of pregnancy, which increases risk factors for both mother and baby.
“A nutritious diet and healthy body weight before conception and during pregnancy are vital. Whereas poor nutrition and excess body weight can change the intrauterine environment, which affects childhood growth and plays a part in the risk of obesity and certain diseases later in a child’s life,” said Dr. Blumfield.
The Dietitians Association of Australia encourage us to focus on the quality of our diet by choosing a wide variety of healthy foods, including plenty of vegetables, along with fruit, wholegrain bread and cereals, lean meats, reduced-fat dairy foods, and healthy fats, from foods like nuts, avocado, and olive oil.
How does lack of sleep affect obesity?
Sustained sleep deprivation has been demonstrated to cause glucose intolerance (trouble breaking down glucose) and insulin resistance (inefficient insulin functioning), both of which result in heightened blood glucose levels. This disruption to blood glucose balance (glycemic control) can nearly double the likelihood of developing Type 2 Diabetes and exacerbate the challenges of managing the condition for individuals living with diabetes.
Studies indicate that sleep deprivation can heighten our hunger and prompt us to reach for comfort foods that are high in fat and carbohydrates. In fact, inadequate sleep may raise our daily energy consumption by roughly 20%. Exhaustion and weariness associated with insufficient sleep also dampen our motivation to engage in physical activity. It is evident that chronic sleep deprivation can elevate the likelihood of weight gain, further exacerbating the challenge of regulating blood glucose levels.
How to improve your sleeping habits
The first step in trying to get a better night’s sleep is to create a good sleep hygiene practice. You can check out our tips for setting yourself up for a good sleep in this article.
If you’re doing everything right that’s within your control, it could be worth consulting with your doctor to have a sleep study carried out. This will allow your health professional to assess your sleep behaviour and determine any underlying issues such as obstructive sleep apnoea. Mild sleep apnoea can be resolved sometimes by simple changes such as modifying your sleeping position, but it’s best to get professional advice.
How much sleep is enough?
According to the National Sleep Foundation, adults between the ages of 18-64 should aim for 7-9 hours of sleep per night. However, individual sleep needs may vary depending on factors such as age, lifestyle, and health status. It’s essential to prioritise getting sufficient rest and adjusting the duration of sleep as necessary to optimise physical and mental well-being.
The Sleep Health Foundation’s 2020 Sleep Health Survey of Australian Adults revealed that on average, Australian adults reported getting around 7 hours and 1 minute of sleep per night on weekdays/workdays and 7 hours and 44 minutes on weekends/non-workdays. However, the study also showed that 33% of Australians reported inadequate sleep duration (less than 7 hours per night) on workdays
What if I'm getting enough sleep, but I'm still tired all the time?
Experiencing fatigue after a restless night of sleep, a hectic workweek, or an overloaded social schedule is common. However, if you find yourself struggling with exhaustion frequently, there may be underlying factors at play.
Fatigue can manifest in various degrees, and medical conditions such as iron-deficiency anaemia, depression, glandular fever, thyroid disorders, or chronic fatigue could be the culprits. It is advisable to consult a healthcare professional who can recommend alternative approaches to restore your energy levels once you have received medical clearance.
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