When it comes to metabolic health, diet and exercise often take center stage. While these factors are undeniably important, sleep is frequently overlooked — despite being a major contributor to overall wellness.
To remain metabolically healthy, prioritizing sleep is a necessity. Here’s why.
Hormonal and Metabolic Effects of Sleep Disruption
Sleep has two main stages: non-rapid eye movement (NREM) and rapid eye movement (REM). NREM includes lighter to deeper sleep stages, while REM is more “active,” resembling wakefulness. Deep (NREM) sleep is particularly important for restoring insulin sensitivity, helping maintain healthy blood glucose levels the next day. However, poor-quality sleep can disrupt this process. And over time, chronic sleep deprivation may lead to an increased risk of insulin resistance, type 2 diabetes, and obesity.
Sleep plays a crucial role in regulating hormones that control hunger, fullness, and blood sugar. Ghrelin, known as the hunger hormone, signals your body to eat, while hormones like peptide-YY, GLP-1, and leptin signal satiety, telling your brain that you’re full. Sleep deprivation can disrupt the balance of these hormones leading to increased hunger and cravings.
Sleep deprivation also interferes with cortisol, a key stress hormone, by delaying its natural peak and keeping it elevated for longer periods of time. This imbalance can make it difficult for your body to regulate stress effectively. Moreover, prolonged elevation of cortisol levels has been linked to increased appetite, abdominal fat accumulation, and insulin resistance.
Melatonin, a hormone produced by the pineal gland in response to darkness, plays a vital role in maintaining the body’s internal clock. It helps promote restful sleep, regulate body temperature, and reduce inflammation. However, poor sleep or exposure to light at night can disrupt melatonin production, leading to reduced secretion. This decrease in melatonin levels may contribute to higher insulin levels and increase the risk of developing metabolic disorders.
The Connection Between Diet and Sleep Quality
What you eat can significantly impact your sleep quality. Diets high in sugar and refined carbohydrates are associated with higher rates of insomnia and sleep disturbances. Eating high-glycemic meals in the evening leads to higher blood sugar levels, which can impair sleep.
On the other hand, consuming adequate protein helps promote restorative sleep. Protein provides amino acids such as tryptophan, a precursor to serotonin and melatonin, which are critical for initiating and maintaining sleep. A recent review of 19 studies found that people who sleep well tend to get more of their calories from protein compared to those who sleep poorly.
Timing of meals matters, too. A large observational study that included more than 100,000 people found that eating or drinking within an hour of bedtime was associated with longer sleep duration but increased wakefulness after falling asleep. Extending the time between eating or drinking and bedtime reduced the odds of disrupted sleep.
The Role of Sleep in Controlling Weight and Food Cravings
The link between sleep and weight is well established. Studies show that people who sleep fewer than six hours per night are at a higher risk of obesity and metabolic issues than those who get seven to nine hours of quality rest. Sleep deprivation alters brain activity by reducing control in decision-making regions and heightening emotional responses, increasing the desire for high-calorie, high-sugar foods which may contribute to weight gain.
How Sleep Helps Regulate Inflammatory Responses
Chronic inflammation plays a major role in the development of metabolic disorders, including cardiovascular disease, type 2 diabetes, and fatty liver disease. Research shows that sleep disruption decreases the production of key molecules responsible for resolving inflammation, with one study finding that their levels remained low even after three days of recovery sleep. Additionally, sleep deprivation increases inflammatory markers such as C-reactive protein, TNF-alpha, and IL-6. Although these changes are typically small, even slight shifts in such markers have been linked to an increased risk of developing metabolic syndrome.
Simple Strategies for Better Sleep
To optimize sleep and improve metabolic health, aim for seven to nine hours of uninterrupted rest each night. Here are some tips that can help:
- Stick to a schedule: Aim to go to bed and wake up around the same time daily, even on weekends.
- Create a sleep-friendly environment: Keep your bedroom quiet and cool to promote restfulness and dark to promote the release of melatonin.
- Limit digital devices in the evening: Reduce screen time and avoid bright lights at least an hour before bed. Using computers, smartphones, and other electronic devices close to bedtime has been strongly linked to insufficient sleep duration and lower sleep quality.
- Watch your caffeine intake: In addition to avoiding eating too close to bedtime, it’s a good idea to minimize caffeinated beverages in the afternoon and evening. A recent systematic review of 24 clinical trials suggests that for most people, the cutoff point for caffeine should be about nine hours prior to bedtime.
- Make exercise part of your daily routine: Studies shows that engaging in moderate-intensity physical activity on a regular basis can enhance sleep quality, decrease the time needed to fall asleep, and improve overall restfulness.
- Eat a well-formulated ketogenic or low-carb diet: Consume adequate protein and fat with small amounts of carbohydrates, mainly from whole foods. For a deep dive on the topic of ketogenic lifestyles and sleep, watch Amber O’Hearn’s presentation Ketogenic Diets, Sleep, and Satiety.
Take Home Message
From regulating hunger hormones to enhancing insulin sensitivity and reducing inflammation, quality sleep is essential for maintaining overall well-being. By making sleep a priority, you can improve your metabolic health and lower your risk of chronic disease.
