Forget running miles or starving yourself skinny. The key to unleashing your body’s full fat-burning potential may be enhancing sleep quality.
The real fat-torching happens while you snooze, according to chiropractor Dr. Mindy Pelz, a fasting and functional health expert.
There are three strategies you can employ before bedtime to sustain your weight loss efforts and take a positive step toward better overall health.
How Do You Burn Fat While Sleeping?
Burning fat while sleeping primarily occurs through a combination of factors, including your metabolism and hormones.
The body’s metabolism is responsible for converting the food you eat into energy. Even when it’s at rest, the body requires energy to perform essential functions like maintaining temperature, digesting food, and sustaining organ functions.
During sleep, the body burns fat stores to power these basic functions.
During sleep, hormone levels fluctuate, and some of them can contribute to fat burning. For example, growth hormone, often referred to as the body’s fat-burning hormone, is released in greater quantities during deep sleep. Growth hormone stimulates fat breakdown and encourages the use of fat for energy.
In addition, inadequate sleep can disrupt the balance of the satiety hormone leptin and hunger hormone ghrelin, potentially leading to increased feelings of hunger and reduced feelings of fullness, which can lead to weight gain.
Sleep improves insulin sensitivity, allowing the body to better use insulin to transport glucose from the blood into cells rather than storing the excess as fat.
One possibility, according to researchers, is that sleep lowers stress, leading to the reduction of the stress hormones cortisol and norepinephrine, which are associated with insulin resistance.
The parasympathetic system, which controls the body’s relaxation response, is activated during sleep, stimulating digestion and metabolic processes like fat metabolism.
3 Tips to Boost Fat Burning
1. Don’t Eat in the Dark
Some research suggests there may be benefits to stopping eating a few hours before bedtime when it comes to weight loss. Melatonin is a hormone produced by the pineal gland in the brain that helps regulate sleep cycles. Melatonin production increases when it’s dark to promote sleepiness, and decreases when it’s light to help with wakefulness.
“Eat when it’s light out because melatonin production is down,” Dr. Pelz said, citing a 2022 study published in Cell Metabolism. “When you’re eating when it’s dark out, your melatonin is going up, so you become more insulin resistant, and your body is not going to be able to make the insulin to drive glucose into the cell,” she added. “That glucose from your meal is going to get stored as fat.”
The study’s researchers found that late eating increased hunger and altered appetite-regulating hormones; when combined, these changes were predicted to increase the risk of obesity.
A randomized, placebo-controlled trial also found that taking melatonin supplements reduces insulin sensitivity in people with Type 2 diabetes.
“We recommend that patients with type 2 diabetes limit their use of melatonin in high doses, as reduced insulin sensitivity is central to the pathophysiology of type 2 diabetes,” the authors wrote.
As a general rule, Dr. Pelz recommends stopping eating at least two hours before bedtime.
Eating your final meal of the day at least three hours prior to going to bed is also recommended by Dr. Joseph Mercola, an osteopathic physician and bestselling author. “It’s one of the easiest, yet most powerful ways to reduce insulin resistance and shrink your waistline,” Dr. Mercola wrote in an article.
2. Keep Your Room Cool
Some research suggests that sleeping in a cool room may activate the parasympathetic nervous system. Sometimes called the “rest and digest” system, it regulates functions like digestion and metabolism, thus helping with fat burning. Parasympathetic activity is switched on when we put ourselves in cool environments, according to research.
“This is like the cold plunges, where you might not have felt that calm when you’re in the plunge, but you will feel calmer afterwards,” Dr. Pelz said. “If it’s summertime, take a very cold shower and then get in bed,” she added.
Lowering the room temperature to 66 F may potentially lead to burning additional calories overnight, a 2014 study observing five healthy male adults for four months found. This is because the body works harder to maintain its core temperature.
After being exposed to mild cold for one month, participants experienced a 42 percent increase in brown fat volume. Brown fat activates in cold temperatures and helps maintain body temperature by generating heat from burning calories. The study also found a 10 percent rise in metabolic activity.
The increases in brown fat and fat-burning metabolic activity declined during the second month when room temperature was kept neutral. In the final month, when participants were exposed to warmer temperatures, the effects were completely reversed back to baseline levels. The researchers noted that these changes occurred regardless of any seasonal variations.
3. Reduce Stress Before Bed
Entering a relaxed parasympathetic state before bed may help sleep.
One proposed way is avoiding emotionally charged conversations in the evening hours. “We have a rule in my house: no stressful conversations before going to bed. We’ll talk about it in the morning,” Dr. Pelz said.
Cortisol, the body’s stress hormone, can promote fat storage when elevated. During sleep, cortisol levels naturally decrease, halting this fat-storing effect. High cortisol signals your body to store more energy to power you through the day, resulting in greater fat retention.
One study found that after two weeks of minor calorie restriction (10 percent less than their daily energy expenditure), participants who were getting 5.5 hours of sleep a night lost 1.3 pounds (0.6 kilograms) of fat, whereas those who slept 8.5 hours each night lost 3.1 pounds (1.4 kilograms) of fat.
Another way to relax before bed is comedy.
Getting into a parasympathetic state means not watching TV before bed, but most people do. If you must, then watch a stand-up comedian, Dr. Pelz said.
“The seriousness of the day is what keeps me in that high-alert beta state, and the minute I laugh, I increase oxytocin and decrease cortisol, sleep a little easier, and get more rest out of my sleep,” she added. “When I get more rest out of my sleep, I’m going to burn more fat.”