Andrew Huberman, Ph.D. is a neuroscientist and tenured professor in the Department of Neurobiology at Stanford University’s School of Medicine. His popular podcast, The Huberman Lab, often covers nutrition and how our dietary choices impact the brain and nervous system. One question Huberman gets frequently - should you eat right before bed or not?
The Quick Answer
Huberman's general recommendation is to avoid large meals within 3 hours of bedtime. A light snack is okay, but any foods too heavy particularly processed foods late at night can negatively affect sleep quality.
To ensure a terrible nights sleep:
— Andrew D. Huberman, Ph.D. (@hubermanlab) July 19, 2022
1) nap more than 90min in the afternoon
2) >100mg caffeine after 4pm
3) eat right before bed time (I confess I do this now and again, as I can’t fall asleep hungry)
4) Sleep in on weekends more than 1hr longer than usual duration
Andrew Huberman discussing his thoughts on bed time eating on his twitter.
The Science Behind Avoiding Large Meals Before Bed
Andrew Huberman dives deep into the biology and neuroscience behind why consuming large, calorie-dense meals right before bed can disrupt sleep quality.
After eating a big dinner, the body needs to direct blood flow to the gut in order to properly digest and absorb the incoming nutrients from the meal. Diverting blood away from the brain decreases sleep pressure. Since feeling sleepy is driven in part by increased blood flow to brain areas like the hypothalamus, having blood shunted to the digestive system instead makes it harder to feel drowsy.
Check out our guide to Nootropics for sleep.
Eating carbohydrate-heavy foods is particularly problematic because of the resulting spike in blood sugar and insulin levels. Insulin triggers tryptophan uptake into muscles rather than letting it enter the brain where it promotes melatonin synthesis. Plus, insulin signals the liver to keep burning glucose instead of depleting glycogen stores, which also impedes sleep hormone release.
The rise in glucose and insulin from nighttime carbohydrate consumption also increases core body temperature, preventing the decrease in body temperature that initiates sleep. Temperature regulation is crucial - even a slight 0.5-1°F drop helps trigger homeostatic sleep drive.
Finally, late night eating leads to fat storage rather than fat burning. Insulin released in response to carbs and protein at night directs the body to store fat. During sleep, insulin sensitivity decreases while growth hormone is normally released to break down fat. So nighttime snacking promotes weight gain.
In alignment with our natural circadian rhythms, the drive for sleep is greatest when we've fasted around 3-4 hours. So from a biological perspective, avoiding substantial calories a few hours before bed optimizes sleep pressure.
Studies on Eating Before Bed
The first study, "Nighttime Eating and Sleep in Young Adults," examined the effects of nighttime snacking on sleep quality and metabolism in a sample of healthy young men. Researchers found that eating snacks closer to bedtime was associated with poorer sleep quality, higher insulin levels, and increased glucose levels compared to eating earlier in the evening. This rigorous controlled study provides evidence of negative metabolic effects from late night eating. However, the sample was small and limited demographically.
The second study, "Eating Habits and Obesity Indices in Sleep Apnea Patients," looked at the relationship between evening meal timing and obesity measures in patients with sleep apnea. They found that eating dinner closer to bedtime was associated with higher BMI and body fat percentage. This study included both men and women with a chronic health condition. However, it relied on self-reported data and had a small sample size.
Finally, the third study, "Eating or Drinking Up to 1 Hour Before Bedtime May Impair Sleep Quality," used data from a large national survey to examine associations between evening food/drink consumption and self-reported sleep quality. They found that eating or drinking within one hour before bed was linked to poorer sleep quality compared to earlier consumption. This study had a large diverse sample and real-world behaviors, but the cross-sectional design prevents causal conclusions.
In summary, all three studies found evidence that eating closer to bedtime has negative effects on sleep and/or metabolism. The controlled lab study provided the most rigorous evidence, while the national survey offered more generalizable real-world data. However, larger randomized controlled trials are still needed to confirm the causal relationships suggested by these preliminary studies.
The Verdict
Based on the research, and what Andrew Huberman generally recommends:
- No large meals within 3 hours of bedtime. Keep dinners light and early.
- Limit carbs, sugars, and proteins that spike insulin at night. Focus on vegetables, healthy fats.
- A small snack like tart cherry juice or almond butter is reasonable if needed.
- Don’t go to bed extremely hungry, as low blood sugar can also disrupt sleep.
While individual needs vary, closing the kitchen a few hours before bedtime, keeping late-night calories light, and sticking to whole foods helps set the stage for more restorative sleep.
Does eating before bed lead to poor sleep?
Eating a large meal right before bed can make it harder to fall asleep and lead to less restful sleep. However, a small, healthy snack a couple hours before bed is less likely to disrupt your sleep.
Why is eating before bed not recommended?
Eating before bed increases your metabolic rate, which can make it more difficult to fall and stay asleep. Late night calories are also more likely to be stored as fat rather than burned for energy.
What types of food should be avoided before bed?
Avoid large portions, spicy foods, fatty foods, and sugary foods in the 2-3 hours before bedtime. These foods can cause indigestion, heartburn, and disruptive blood sugar changes.
Are there any benefits to eating before bed?
A small snack high in carbohydrates or protein consumed 1-2 hours before bed may help induce sleepiness and prevent low blood sugar during the night. However, the drawbacks tend to outweigh benefits for most people.
What if you are hungry close to bedtime?
If you feel hungry before bed, opt for lighter options like whole grain crackers, cereal and milk, yogurt, or fruit to promote satiety without disrupting your sleep and metabolism too much. But try to finish eating 1-2 hours before laying down.
What are some better habits for good sleep?
Avoiding screens, establishing a calming bedtime routine, keeping your room cool and dark, and going to bed at a consistent time are some healthy sleep habits to follow instead of nighttime snacking.
