What happens inside of you when you eat late at night? In this post, we’ll take a look inside to better understand how that snack you eat at bedtime affects your weight, blood sugar, and sleep.
Bedtime Snacking At-A-Glance
- Bedtime snacking promotes weight gain and reduces fat oxidation (breakdown)
- Eating late at night can result in higher fasting blood glucose readings in the morning
- Late-night snacking raises your core body temperature, interfering with sleep
- Having a full stomach at bedtime can worsen heartburn
- You can reduce heartburn, sleep better, and lower your odds of gaining weight when you stop eating three hours before bed.
Bedtime Snacking: Here’s What Happens Inside You [Video]
In this video, you’ll learn…
- How late night snacking affects your weight, sleep and general health.
- How to avoid the negative affects of late night snacking.
- Additional strategies for weight loss!
Bedtime Snacking Promotes Weight Gain
When 133 young women were evaluated based on their eating and sleeping habits, researchers found that those who ate closest to bedtime carried the most body fat (BMI) and had the highest waist measurements (1).
This study did not look for a specific time at night to stop eating. Instead, they looked at the elapsed time between your last meal and the midpoint of sleep.
For instance, if you sleep for 6 hours, the midpoint of your sleep would be 3 hours. Therefore, according to this study, it doesn’t matter if you are an “early to bed and early to rise” person or a true “night owl.” What mattered was the length of time you went without food before bed and how long you slept.
However, that doesn’t mean that the timing of your calorie intake is unimportant. A group of older individuals was fed the same amount of calories on two different occasions.
On the first occasion, they ate a large breakfast, followed by lunch and dinner. In the second session, they shifted their eating schedule to include lunch, dinner, and a large bedtime snack. Even though the total daily energy and nutrient intake was equivalent between the sessions, switching the calories from breakfast to bedtime had a significant impact on the way their bodies used the food.
The late-night eaters burned the carbohydrates in the meal at the expense of fat breakdown. Scientists refer to the breakdown of fat as lipid oxidation. And, when there is a reduction in lipid oxidation, the result is an increase in fat storage, which over time, will lead to increased weight gain (2).
Elevates Fasting Blood Glucose Readings
A late-night intake of carbohydrates will have another consequence that you don’t want, which is increased blood sugar and insulin levels overnight.
Not only will those elevated levels block your body’s ability to burn fat as you sleep, but you can also wake up with a higher fasting blood glucose reading in the morning. If you are someone at risk for diabetes, you know that your morning blood glucose level is a factor that your doctor follows closely.
Bedtime Snacking and Insulin Resistance
The lack of ability to properly use calories when consumed late at night may be related to the way hormones are naturally produced as your body prepares for sleep.
At night, your body becomes less sensitive to insulin. Insulin is your energy-storing hormone. When you lack insulin sensitivity, your body can’t utilize carbohydrates and other food nutrients as efficiently.
Melatonin, which is a hormone that you probably associated with sleep, plays a role in this nightly insulin resistance. Melatonin naturally increases as we get closer to falling asleep. However, as melatonin goes up, insulin secretions go down (3).
As melatonin prepares us for sleep, our cells become less tolerant of the carbohydrates that we eat.
Interferes with Sleep
Speaking of sleep, another thing that happens inside your body when you eat late at night is that your core body temperature rises. This is due to the heat produced by the digestion of food.
Digestion is an energy-intensive process. To make sure the job gets done, your body increases blood flow to your digestive tract, which elevates your core temperature, making it harder to get a restful night’s sleep.
Also, if you suffer from heartburn, bedtime snacking can make your symptoms worse (4).
This is due to the pressure a full stomach puts on the barrier between your esophagus and stomach. When you lie down with a full stomach, you take away the advantage you gained from gravity, making it easier for stomach acids to head back toward your throat.
Bedtime Snacks FAQs
How long must I avoid food before bed?
This answer will vary depending on how much you eat, but studies support that you can reduce heartburn, sleep better, and lower your odds of gaining weight when you stop eating three hours before bed (4) (5).
What if I can’t sleep without food?
The avoidance of bedtime snacking has many health and weight loss advantages. But what if you simply cannot sleep because you are too hungry at night? If you feel this way, it may be due to the overall content of your diet.
When study participants ate different diets, they slept differently. The research teams found that a high-carb diet puts us to sleep quickly (6).
However, we get our best night’s sleep when we eat foods high in protein or fat. Studies that compared diets and sleep metrics found that high-protein and high-fat diets lead to fewer episodes of waking up and overall better quality sleep when compared to a control diet (6) (7).
What you eat and when you eat it matters. For enhanced weight loss, better blood sugar control, and your best night’s sleep, make sure your diet contains healthy fats and proteins and that you stop eating three hours before bed.
That 3 hours before bed rule is one of my 4 daily habits for weight loss. You can learn the other three habits by downloading my 0,1,2,3 strategy. It is a foundation that is already being used by 10’s of thousands of people!
Thanks for reading and have a wonderful week!
(1) Zerón-Rugerio, María Fernanda, et al. “The Elapsed Time between Dinner and the Midpoint of Sleep Is Associated with Adiposity in Young Women.” Nutrients 12.2 (2020): 410.
(2) Kelly, Kevin Parsons, et al. “Eating breakfast and avoiding late-evening snacking sustains lipid oxidation.” PLoS biology 18.2 (2020): e3000622.
(3) Peschke, Elmar, Ina Bähr, and Eckhard Mühlbauer. “Melatonin and pancreatic islets: interrelationships between melatonin, insulin and glucagon.” International journal of molecular sciences 14.4 (2013): 6981-7015.
(4) Fujiwara, Yasuhiro, et al. “Association between dinner-to-bed time and gastro-esophageal reflux disease.” (2005): 2633-2636.
(5) Xiao, Qian, Marta Garaulet, and Frank AJL Scheer. “Meal timing and obesity: Interactions with macronutrient intake and chronotype.” International Journal of Obesity 43.9 (2019): 1701-1711.
(6) Lindseth, Glenda, Paul Lindseth, and Mark Thompson. “Nutritional effects on sleep.” Western journal of nursing research 35.4 (2013): 497-513.
(7) Lindseth, Glenda, and Ashley Murray. “Dietary macronutrients and sleep.” Western journal of nursing research 38.8 (2016): 938-958.
About the Author
Becky Gillaspy, DC graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991.