What foods increase cortisol before bed?

January 6, 2026 •

4 min read

According to research from Johns Hopkins Medicine, eating a late meal can cause a significant spike in blood sugar and an increase in cortisol levels, particularly for early risers. This hormonal disruption is a key reason to understand what foods increase cortisol before bed and how they sabotage a good night's rest.

Quick Summary

Several common late-night food and drink choices can raise the body's stress hormone, cortisol. Items high in refined sugar, caffeine, and alcohol disrupt the natural sleep-wake cycle by causing blood sugar imbalances and suppressing melatonin production. Avoiding these foods in the evening supports healthier cortisol levels and improves sleep quality.

Key Points

Refined Sugars: Eating high-sugar foods before bed can cause blood sugar spikes and crashes, triggering cortisol release and disrupting sleep.
Caffeine and Stimulants: Drinks like coffee, tea, and energy drinks boost cortisol and block sleep signals, with effects lasting many hours.
Alcohol: Though it can cause initial drowsiness, alcohol consumption increases cortisol later in the night and fragments sleep.
Processed and Fried Foods: These foods promote inflammation and metabolic stress, which can lead to elevated cortisol levels.
Late-Night Meals: Eating large meals close to bedtime, especially those high in fat and sugar, can elevate nocturnal cortisol and delay melatonin onset.
Balanced Diet is Key: Counteract stress and cortisol spikes by eating balanced meals rich in fiber, whole grains, omega-3s, and magnesium.
Timing Matters: Consuming a light, nutrient-dense snack a few hours before bed is preferable to a heavy, sugary or fatty meal.

Understanding the Cortisol and Sleep Connection

Cortisol, often called the “stress hormone,” naturally follows a circadian rhythm, with levels peaking in the morning to wake you up and gradually decreasing throughout the day to support restful sleep. However, certain dietary choices, especially before bed, can interfere with this natural cycle, leading to elevated cortisol at night. High cortisol at night suppresses the production of melatonin, the sleep hormone, making it harder to fall asleep and stay asleep.

The Dietary Culprits That Elevate Nighttime Cortisol

Many common foods and beverages can cause an unwanted spike in your cortisol levels just when they should be at their lowest. By consuming these items in the hours before sleep, you signal to your body that it needs to be alert and active, not winding down for rest.

Refined Sugars and High-Glycemic Foods: This includes sweets, pastries, white bread, and sugary drinks. These foods cause rapid spikes in blood sugar, prompting the pancreas to release insulin. The resulting blood sugar crash can trigger the adrenal glands to secrete cortisol to bring glucose levels back up, creating a metabolic stress cycle that disrupts sleep.
Caffeine: Caffeine is a potent stimulant that directly increases cortisol production and blocks adenosine, a brain chemical that promotes relaxation and drowsiness. Its stimulating effects can last for hours, disrupting deep sleep. This includes coffee, many teas, energy drinks, and even dark chocolate.
Alcohol: While alcohol may initially make you feel sleepy, it disrupts the sleep cycle and raises cortisol levels later in the night. It interferes with the natural production of melatonin and can cause a rebound effect that fragments sleep and increases wakefulness in the early morning.
Processed and Fried Foods: Fast food, chips, and other processed snacks are often loaded with unhealthy fats, added sugars, and sodium. These ingredients can cause inflammatory responses in the body, which can trigger cortisol production.
Excessive Animal Protein and Saturated Fat: Some research suggests that diets high in animal proteins, saturated fats, and salt can negatively impact the natural circadian production of cortisol.

Comparison of Sleep-Disrupting vs. Sleep-Promoting Foods

Making the right food choices can be a powerful tool for regulating cortisol and supporting healthy sleep. This table outlines the stark difference between foods that harm sleep and those that help it.


Food/Beverage Type	Impact on Nighttime Cortisol & Sleep	Recommended Alternative	Rationale for Alternative
Sugary Snacks	Rapid blood sugar spikes followed by crashes, triggering cortisol release.	Bananas or Oats	Contain magnesium and complex carbs that promote relaxation and sustained energy.
Caffeinated Beverages	Directly increases cortisol and blocks sleep-inducing adenosine.	Chamomile Tea	Has mild cortisol-lowering and calming effects, promoting relaxation.
Alcohol	Disrupts sleep cycle and elevates cortisol hours after consumption.	Water or Herbal Tea	Hydrates the body and avoids the stimulating and disruptive effects of alcohol.
Greasy, Processed Foods	Causes inflammation and metabolic stress, raising cortisol.	Leafy Greens or Nuts	Rich in magnesium and anti-inflammatory omega-3s to support cortisol regulation.

Strategic Eating for Healthy Cortisol Levels

Optimizing your diet for sleep involves more than just avoiding certain foods; it's also about strategically incorporating helpful nutrients. Magnesium is a vital mineral that helps regulate cortisol and promotes muscle relaxation. Foods rich in omega-3 fatty acids, like fatty fish, have anti-inflammatory properties that help manage the stress response. Additionally, L-theanine, an amino acid found in green tea, can reduce stress-related symptoms and lower cortisol.

Consider incorporating foods like spinach, avocados, nuts, fatty fish, and whole grains into your evening meal or a light, early snack. Maintaining stable blood sugar levels by pairing complex carbohydrates with protein and healthy fats helps prevent the overnight blood sugar crashes that can trigger a cortisol spike. Regular, balanced meals and proper hydration throughout the day also contribute to a healthy cortisol pattern. Timing is also important; aim for your last major meal to be a few hours before bedtime to allow for proper digestion.

A Concluding Thought on Dietary Choices and Rest

The link between diet and sleep is undeniable. Consuming foods that increase cortisol before bed creates a hormonal and metabolic stress signal that is the opposite of what your body needs to wind down. By being mindful of your evening food and drink choices, you can effectively support your body's natural circadian rhythm, paving the way for lower cortisol levels, better sleep quality, and improved overall health.

The Importance of Consistency

It is crucial to remember that consistency is key. A single night of poor dietary choices is unlikely to cause long-term damage, but a consistent pattern of consuming sleep-disrupting foods can throw your body's hormonal balance out of sync. Integrating regular exercise, stress management techniques, and a consistent sleep schedule alongside a nutrient-rich, anti-inflammatory diet can lead to significant and lasting improvements in both your sleep and overall well-being. For more on optimizing your sleep health, read about the benefits of good sleep hygiene.

Frequently Asked Questions

Sugary snacks are bad for sleep because they cause a rapid increase in blood glucose. As your body produces insulin to manage this sugar, it can overshoot and cause a blood sugar crash during the night. This crash is perceived as a stressor by the body, prompting the adrenal glands to release cortisol, which wakes you up.

You should generally avoid caffeine for at least 6 hours before your planned bedtime. For individuals more sensitive to its effects, limiting caffeine to the morning or avoiding it after noon may be necessary to prevent sleep disruption.

Yes, alcohol does disrupt sleep even if it initially makes you feel tired. It leads to fragmented sleep and causes an increase in cortisol levels later in the night, which suppresses melatonin and can cause you to wake up.

No, not all carbohydrates are bad before bed. The key is the type and timing. Refined and simple carbohydrates can cause harmful blood sugar spikes, but complex carbohydrates found in oats and whole grains provide more sustained energy and are less likely to disrupt cortisol or blood sugar levels.

Foods that help lower cortisol include those rich in magnesium and omega-3 fatty acids. Examples are leafy greens, avocados, nuts, fatty fish like salmon, and whole grains.

Yes, even mild dehydration can act as a physical stressor, triggering cortisol release and negatively impacting your sleep. Staying properly hydrated throughout the day is important for maintaining healthy cortisol patterns.

Late-night eating, especially of high-sugar or high-fat foods, can misalign the body's circadian clock and elevate cortisol for many people, especially 'early birds'. However, some individuals, like 'night owls,' might be less affected metabolically, though it's still generally advised to avoid disruptive foods before sleep.