From keto to lifting, you might feel more bombarded with weight loss advertisements on social media and websites than ever.
A new diet or workout plan promises to help you shed those extra pounds every day.
And while some may be perfectly safe and work for a select few, many of these programs could be more effective and sustainable.
Interestingly, researchers suggest that the key to weight loss may not only be related to moving more or eating less — it's actually about getting enough sleep.¹
The results are consistent across studies conducted with various age groups across different locations over the past decade.
One prominent longitudinal sleep study followed 68,000+ middle-aged women over 16 years.
The researchers found that over this timespan, women who slept for 5 hours or less per night put on 1.14 kg more than those who got 7 hours of sleep each night over 16 years.
The women who slept 6 hours per night also gained 0.71 kg more than those in the 7-hour category.²
Another study found that sleeping more can also affect the type of weight that you lose.
The randomized crossover trial published in the Annals of Internal Medicine found that people who slept for 8.5 hours per night burned more fat than those who slept for 5.5 hours per night (even though both groups lost the same amount of weight on average).
Interestingly, both groups had the same calorie-restriction diet.³
Here's what science shows about the connection between sufficient sleep about losing weight.
As your body rests, it goes through various physiological changes related to metabolism and hunger.
Here's how getting enough sleep at night may help you to maintain a healthy weight:⁴
Sleep plays an essential role in regulating appetite by affecting the levels of two hormones in your body: leptin and ghrelin.
Fat cells produce leptin and signal the brain when you are full.
On the other hand, ghrelin is made by the stomach and signals the brain when you are hungry.
Studies have shown that when sleep deprived, our bodies produce more ghrelin and less leptin. This leads to increased hunger and cravings.⁵ ⁶
The stress hormone cortisol also increases when you don't get enough sleep, leading to increased appetite and cravings for high-fat and high-sugar foods.⁷
Therefore, having difficulty limiting what you eat while sleep-deprived isn't just a matter of a lack of willpower. There are physiological changes also driving you to eat more.
Achieving weight loss is commonly explained through energy balance — ensuring the number of calories going into our body (eating) is less than the calories we use (exercise).
A recent randomized clinical trial demonstrated that participants could reduce the calorie intake aspect of this energy balance by sleeping a healthy number of hours each night (about 7–9 hours).
The study published in JAMA Internal Medicine involved 80 overweight adults who regularly slept less than 6.5 hours a night.
Some entered a sleep intervention group. Through sleep hygiene counseling provided by the research team, the participants in this group extended their sleep duration by about 1.2 hours per night.
In contrast, the control group resumed their regular sleep schedules.
All of this also took place in a real-world setting. Participants were tracked using wearable devices while sleeping in their beds at home.
Interestingly, those in the intervention group got more rest each night and were able to lower their caloric intake (by about 270 calories a day) compared to the control group.
This finding was significant because it showed that you might reduce the calories you consume simply by getting adequate sleep. Also, participants made no changes to diet or activity habits.⁸ ⁹
The study did not formally examine why the intervention group had a reduction in their calorie intake. But other research suggests that being well-rested can affect food choices, such as selecting healthier foods over ultra-processed foods.
It's well-established that lack of sleep can impair decision-making. So when it comes to making choices about food, you might listen to cravings or opt for high-sugar foods when tired.¹⁰ ¹¹
Being sleep-deprived also means you have more awake hours, opening up more opportunities for unhealthy eating behaviors.
Interestingly, catching up on sleep over the weekend doesn't make things better. The study which demonstrated this compared three different sleep groups:
Group 1 Participants were consistently sleep deprived (sleeping 5 hours a night).
Group 2 Participants slept 5 hours on the weekdays plus two days of recovery sleep on the weekends.
Group 3 Participants had consistent 9-hour sleep blocks.
They found that the first and second groups were more likely to eat after dinner. Furthermore, their average body weight also increased compared to Group 3.¹² ¹³
In addition to changing food consumption behavior, sleeping less can also alter your brain chemistry to encourage more eating.
Your brain’s reward system is always looking for a tasty treat. These circuits release dopamine, a neurotransmitter that makes us feel pleasure and motivates us to seek rewarding experiences.
However, sleep deprivation can disrupt our brain's habitual response to food. A 2012 study published in The American Journal of Clinical Nutrition compared sleep-deprived individuals with people who slept a recommended number of hours and assessed their neurological reactions to food.
Under the sleep-restricted condition, participants only slept for 4 hours a night. While in unrestricted sleep, they slept for 9 hours. Each sleep phase lasted 6 days, and a functional magnetic resonance imaging (MRI) brain scan assessed brain activity.
After sleep deprivation, the brain scan revealed more activity in areas of the brain that give us a sense of reward and pleasure (like the putamen and nucleus accumbens) in response to food images. Enough rest reduced this effect.
If your brain responds more strongly to food cues when sleep-deprived, it could be more challenging to resist temptation and increase your chances of making poor food choices or overeating.¹⁴
Sleep deprivation can also cause changes in how your body metabolizes glucose (blood sugar) which can play a role in developing chronic conditions like diabetes and obesity.
Usually, your body regulates blood sugar levels by releasing insulin in response to rising glucose levels. One study published in the Sleep Journal compared how well participants' bodies broke down glucose after two consecutive nights of 4 hours of sleep versus two successive nights of 8 hours.
The glucose metabolism markers included measurements of blood glucose and insulin levels.
Initially, the researcher didn't find any difference in these markers between the two test conditions before breakfast. However, once participants ate their first meal of the day, the sleep-restricted group had significantly higher insulin and glucose levels in their bloodstream.
Any glucose your body doesn't need for energy accumulates in your liver and muscles as glycogen. However, your body can't store unlimited amounts of glycogen. Once your glycogen stores are full, any extra glucose is converted to fat and stored in your fat cells — ultimately leading to weight gain.¹⁵ ¹⁶
Sleep and exercise also have a significant two-way relationship.
Several studies have found that getting sufficient exercise promotes better rest by reducing the time it takes you to fall asleep as well as increasing the overall time you sleep.¹⁷
Whether or not more sleep can translate to more exercise needs further examination.
While it sounds logical that when you're less tired, you’d be more motivated to go for a run or hit the gym, one study found that improved insomnia (through behavioral treatments) did not increase participants' overall (daily) physical activity. However, individuals struggling with insomnia were more likely to report reduced activity and fitness levels.
So, researchers posit that better sleep alone may be insufficient to modify daily activity habits. But it's certainly an area of study that needs more research.¹⁸ ¹⁹
As obesity rates soar, finding scientifically-backed weight loss methods is a crucial mission for public health organizations across the globe.
According to the World Health Organization, global obesity rates have tripled between 1971–2021. Based on data collected in 2016, more than 1.9 billion adults above 18 years old were overweight. 650 million of these individuals are clinically obese.²⁰
The United States has the 12th highest rate of obesity in the world.
According to the Centers for Disease Control and Prevention, obesity prevalence among adults was 41.9% in 2017.²¹ ²²
The COVID-19 pandemic also seemed to worsen the problem, with 16 states surpassing the 35% obesity rate. Back in 2011, no states had passed that threshold.
With people confined mainly to their homes during that period because of lockdowns, this created more sedentary behavior. Increased stress during that time may have also affected peoples' food choices.²³
This widespread issue doesn't just affect peoples' appearances or fitness. It poses a significant health risk for many other chronic diseases, such as heart disease, stroke, diabetes, and certain types of cancer.
Being overweight can lead to plaque buildup, narrowing the arteries and making it harder for blood to flow through them. Over time, this can lead to increased blood pressure and even a heart attack or stroke.²⁴ ²⁵
Fortunately, there are steps to manage your weight.
Go to bed early Aim to go to bed at a time that allows you to get 7-9 hours of sleep.²⁶
Maintain a regular sleep schedule It's best to go to bed and wake up at roughly the same time every day, rather than try to “catch up” on sleep over the weekend. Consistency helps to keep your internal body clock in sync.
Create an environment that helps you sleep Keep your room as dark as possible, and think about what helps you feel comfortable. Do you need a quiet environment? Or maybe some white noise might help?
Limit screen time before bed Try to stop using devices at least 30 minutes before bedtime because the light they emit can disrupt your internal body clock.
Be mindful of what you consume just before bedtime Try to avoid stimulants like nicotine and caffeine. Alcohol is both a stimulant and a depressant and can interfere with sleep. Avoid going to bed too close to eating, as it can create discomfort and trigger acid reflux (GERD).
Manage stress When you have a lot on your mind, it can make it harder to fall asleep. While awake, you might even eat comfort foods to cope with strong emotions, which also lends to weight gain. Explore different ways to cope with stress to achieve better rest.
Ensure your daytime schedule aids your sleep schedule Try not to take lengthy daytime naps, as it can affect how easily you fall asleep at night.
Exercise regularly, but not just before bedtime Regular physical activity can help to promote more restful sleep (it helps with weight loss too). However, try not to be too active closer to bedtime as it can cause you to feel energized and stimulated, making it harder to fall asleep.
Keep bedroom temperature cool and your feet warm Evidence supports that keeping your toes toasty warm can contribute to falling asleep faster and having a better night's sleep.
Your sleep habits can impact hunger hormones, calorie intake, food choices, metabolism, physical activity in a day, and even how your brain reacts to food. So if you’re looking to manage your weight, prioritize getting plenty of restful sleep. It may not be the only thing you need to do, but it’s an excellent place to start.
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Obesity prevention source | Harvard T.H. Chan
Why sleep is so important for losing weight | The Conversation
Getting more sleep reduces caloric intake, a game changer for weight loss programs | The University of Chicago
Obesity and overweight | World Health Organization (WHO)
Global obesity levels | Procon.org
Adult obesity facts | Centers for Disease Control and Prevention (CDC)
Obesity and chronic disease | Alabama Public Health
How much sleep do I need? | Centers for Disease Control and Prevention (CDC)
Dawn Teh is a health writer and former psychologist who enjoys exploring topics about the mind, body, and understanding what helps humans thrive.
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