06 Sep Everything You Need To Know About The Circadian Rhythm Diet
Making smart food choices is the key to eating and living healthy. But now, the latest research shows that when we eat is just as important as what we eat.
Why, you ask? Because as it turns out, biological activities like metabolism are closely linked to our circadian rhythm. “Your metabolism changes throughout the day because of your circadian rhythm or natural body clock,” tells Jessica Tong, a Vancouver-based registered dietitian. “In the morning, in response to daylight and food, insulin sensitivity increases and melatonin decreases, making you feel alert and energized. Meanwhile, in the evening, melatonin levels go up and insulin sensitivity decreases, preparing your body for rest and cell repair,” she explains.
Experts argue that aligning your mealtime with your circadian rhythm can help maximize weight loss, improve endurance, reduce the risk of type 2 diabetes and lower blood pressure, among other things.
But firstly, what exactly is circadian rhythm?
“Your circadian rhythm is basically a 24-hour internal clock that is running in the background of your brain and cycles between sleepiness and alertness at regular intervals. It’s also known as your sleep/wake cycle,” states the National Sleep Foundation.
“Sleep affects two hormones in the body, which regulate hunger—ghrelin and leptin. Ghrelin stimulates your appetite while leptin does the opposite,” tells Harley Pasternak, celebrity nutritionist, personal trainer and author of The Body Reset Diet Cookbook. “When your body is sleep-deprived it throws off your circadian rhythm, increasing ghrelin levels and decreasing leptin in the body—which can lead to increased hunger and sugar cravings,” he points out.
Besides inadequate shut-eye, other factors like jet lag, medications and irregular work hours can also mess with your circadian rhythm.
“A disrupted circadian rhythm may lead to increased production of insulin in your body,” says Tong. Insulin is a hormone that’s responsible for helping the cells in our body metabolize and properly use nutrients obtained from food. “Chronically elevated insulin levels can result in an increased risk of developing cardiovascular disease and type 2 diabetes,” notes the dietitian.
What are circadian rhythm disorders?
Circadian rhythm disorders are a group of conditions that occur when your circadian rhythm – most commonly your sleep-wake cycle is not properly aligned with your environment and interferes with your daily activities.
Common circadian rhythm disorders include:
- Jet Lag or Rapid Time Zone Change Syndrome: Most of you have experienced jet lag the occasional time when you travel across time zones, however for those in which it is a regular occurrence you know all too well the sleepiness and lack of daytime alertness that is common. This typically is amplified with each time zone crossed, especially when traveling toward the east.
- Shift Work Sleep Disorder: This disorder affects those who frequently work shift work or work at night. For some their genetics allow an easier transition while others experience a dramatic impact meaning that they can get up to 4 hours less sleep a night compared to the average person.
- Delayed Sleep Phase Syndrome (DSPS): This is a shift in circadian rhythm and a disorder of sleep timing. Those with DSPS are wired to fall asleep very late resulting in a difficult time getting up in the morning as opposed to “night owls” who choose to go to bed late. Research shows that there is a higher incidence of depression in people with DSPS.8 DSPS is common in teens and young adults.
- Advanced sleep phase syndrome (ASPS): This is a disorder in which a person goes to sleep earlier and wakes earlier than desired. For example, they might fall asleep between 6 and 9 p.m. and wake up between 1 and 5 a.m
- Irregular Sleep-Wake Rhythm Disorder (ISWRD): With this disorder, there is lack of a circadian rhythm pattern of sleep and wake. Individuals will sleep at variable times throughout the day and night. They may often sleep is a series of naps of variable length during a typical 24-hour day.
- Non-24 Hour Sleep-Wake Rhythm Disorder (N24): In this condition an individual’s biological clock is not aligned with a 24–hour day. N24 sufferers will typically have their sleep time gradually delaying by minutes to hours every day. This often affects those who are blind due to lack of the light-dark cycle.
What are the signs and symptoms of circadian rhythm disorders?
Symptoms that have lasted for three months or more may indicate a circadian rhythm disorder. One of the first symptoms is often sleep difficulties.4 Common symptoms of circadian rhythm dysfunction include:
- Consistent difficulty falling asleep, staying asleep, or both
- Nonrestorative sleep (feeling tired even after getting enough sleep)
- Daytime sleepiness or sleepiness during shift work
- Fatigue, exhaustion, lethargy
- Impaired performance
- Poor concentration
- Decreased alertness
- Reduced psychomotor coordination
- Impaired judgment and trouble controlling mood and emotions
- Aches and pains, including headaches
- Digestive distress
- Stomach problems, in people who have jet lag disorder
Ultimately sleep deprivation can change how your brain perceives risky situations and you may underestimate the risks and overestimate the rewards of situations. This may lead to riskier behaviors than what you would normally choose when well rested leaving yourself and others at an increased susceptibility to danger. Thus, keeping your circadian rhythm in check is important to stay mentally and physically healthy.
How does your circadian rhythm impact your mood?
Irregular circadian rhythms send mixed messages to the body. A study published in The Lancet Psychiatry has found that disruptions to your internal clock may increase the risk of mood disorders including depression, anxiety, bipolar disorder and seasonal affective disorder (SAD) by up to 10 percent.
In particular if one’s circadian rhythm is dysfunctional, there is a greater association within mood disorders towards major depressive disorder and bipolar disorder. It has been suggested that those who are night-owl type may have a greater predisposition to mood disorders.10 It was also found that night owls tended to be lonelier and more unhappy. Early risers tend to have healthier breakfasts and are less likely to procrastinate– all habits of highly successful people and great reasons to go to bed earlier.
Circadian Rhythm Diet 101
“Your natural body clock is synchronized with your external environment through cues like exposure to light and the timing of your meals,” says Tong. The circadian rhythm diet, also known as the body clock diet, is basically a form of time-restricted eating plan where you eat in sync with this internal clock.
“This means that you eat during the daylight hours, within a window of 12 hours or less and fast for the remaining 12 or more hours each day,” Tong explains. “Ideally, aim to make breakfast and lunch your larger meals and dinner your smaller meal of the day,” she suggests.
While anyone can benefit from this diet, it’s particularly suitable for people who have metabolic diseases, like obesity and type 2 diabetes, says Tong. “It may also help those who are trying to cut down evening or late-night snacking and require some boundaries to help break the habit,” she adds. But before you kickstart your new diet, don’t forget to speak with your doctor or dietitian first, Tong advises.
How to do time-restricted eating right
For beginners, Pasternak suggests dividing your calorie intake into three main meals and two snacks, with the four pillars of food included in every meal—a high-quality protein (like fish or dairy), plenty of vegetables, a handful of quality fiber and healthy fats. “I also recommend incorporating fermented foods in your daily meals. Yogurt and cheese are some great options,” adds the nutritionist.
Additionally, have your morning meal within two hours of waking up. A typical healthy breakfast consists of key nutrients like protein, fiber, vitamins and healthy fats. “One of my favorite go-to meals in the morning is a smoothie. I like to hide some of my nutrients in there,” says Pasternak. “I like to throw in nuts, avocado, berries, whey protein, even fermented dairy in it,” tells the fitness expert.
At night, go for a lighter meal like baked salmon, black bean soup, avocado toast or a salad bowl.
Pasternak also suggests having a glass of warm milk as you wind down for bed as it may help you sleep better. “Some studies indicate that tryptophan, an essential amino acid found in milk and other protein-packed foods, may have a calming effect,” he says.
More importantly, “note that just because you are eating within a time-restricted window doesn’t mean that it’s okay to make poor food choices during this time,” says Tong. “Choosing nutrient-dense foods and practicing portion control is still important,” she adds.
Other than that, aim for at least seven hours of sleep each night, says Pasternak. “Cut out caffeine after noon, shut down electronics 30 minutes before bed and—if you need to—listen to a sound machine at night to drown out noises that may disrupt your sleep,” he suggests.
And lastly, try to be consistent with your routine— because the more regular your sleeping and eating habits are, the better your circadian rhythm works.