Sleep is important. We all know how it feels the next morning when we don’t get enough sleep the night before—whether we’re up with a sick kid, a night with friends goes later than planned, or you’re tossing and turning, trying to get comfortable—we can’t seem to function the next day, and that second, or let’s face it, third cup of coffee isn’t cutting it. It’s downright miserable, and the thought of getting into your cozy space without an alarm sounds heavenly.
But sleep goes much deeper than that, and what you might have previously thought was just environmental factors that affected your sleep patterns isn’t completely accurate. So if you’ve ever thought of yourself as either a morning (good morning, morning lark!) or a night person (good evening, night owl), there’s science-backed research that actually shows there’s a biological reason why. In fact, your ideal bedtime schedule depends on your sleep chronotype, meaning your circadian preference for either mornings or evenings. And your sleep chronotype may affect how you lose weight. Let’s dive in.
Scientists believe that our bodies are evolutionarily hard-wired to fall into one of three main sleep chronotypes: morning type, evening type, or intermediate type. Essentially, sleep chronotypes dictate your preference for when you like to sleep and be awake over a 24-hour period. So sleep chronotypes aren’t about environmental factors like your job, having a newborn baby, or experiencing jet lag after a long cross-country trip. Instead, they’re intrinsic and influenced by your genetic makeup. As a matter of fact, your specific sleep chronotype can be inherited.
Even more, you’re most likely familiar with terms like early bird or night owl when describing someone’s daily rhythms. (Recognize yourself?) And just like they sound, the early chronotype people prefer mornings, while the late chronotype folks prefer evenings, like to wake up later, and are more alert and motivated in the evening or night. Interestingly enough, researchers hypothesize that these biological traits are evolutionary and were a way for early humans to survive by switching watch shifts—if someone was awake at all times, it lowered the risk of a late-night threat in the dark.
Turns out, depending on your sleep chronotype, you may be more prone to developing obesity. Indeed, an examination of data from Louisiana's Bogalusa Heart Study published in 2020 in Chronobiology International: The Journal of Biological and Medical Rhythm Research found that among middle-aged white participants, those with an evening chronotype were independently associated with obesity. That means that regardless of physical activity, shift work, or sleep duration, they had a greater risk of obesity. (Conversely, the findings also found that a morning chronotype may be preventative.)
On top of that, a meta-analysis of 27 studies published in 2022 in the journal Frontiers in Endocrinology concluded that compared with a morning chronotype, people with an evening chronotype had a higher body mass index (BMI) and higher blood sugar and total cholesterol levels. This is significant because these factors can influence the ability to lose weight and may mean you could be predisposed to having a more difficult time trying to lose weight.
And an evening type is associated with “poorer” lifestyle behaviors that can contribute to overweight and obesity. Some of these include eating larger meals and getting the most calories later in the day, finding difficulty getting physical activity in as a “night owl,” and having a greater risk of cardiovascular issues because of smoking. In one study, night owls were more than twice as likely to smoke tobacco than intermediate types and had more screen time, according to an analysis of population data from about 440,000 adults in the UK Biobank and published in 2016 in the Annals of Behavioral Medicine: A Publication of the Society of Behavioral Medicine.
To be perfectly clear, if you’re an evening type, it doesn’t mean you’re doomed on your weight-care journey or your ability to live a healthy lifestyle. It just means you need to make adjustments and healthy habit changes according to your chronotype. You can take a free quiz here from clinical psychologist Michael Breus, PhD (The Sleep Doctor) to find out your chronotype.
If you do discover you’re an evening type, here are a few tips and tricks to help make your weight-care journey manageable:
Eat breakfast. As an evening type, breakfast often gets skipped, but it’s important to eat calorie-dense meals earlier in the day. Shifting the majority of your calorie intake earlier in the day may help reduce late-night snacking.
Avoid alcohol at night. For those who have an evening chronotype, alcohol may hinder weight-loss goals and targets.
Get extra support. Using your community or an accountability partner to help you stay on track will be super important because it may be harder for you to stick to habits and easier to relapse.
Exercise at a time that makes you feel happy. Physical activity is crucial for everyone, but maybe the first-thing-in-the-morning gym routine isn’t for you. Try evening walks or a later workout at a time that safely works for you.
Found is among the largest medically-supported weight care clinics in the country, serving nearly 200,000 members to date. To start your journey with Found, take our quiz.