Longevity Hack

Diet study reveals optimal number of hours to sleep to boost good snack habits

If you needed another reason to prioritize sleep...

A woman standing in front of the open refrigerator at late night to get a snack
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When we fall asleep, where do we go? If you are Billie Eilish, it’s top of the charts, but for the rest of us — scientists included — the answer is a mystery. But we all sleep, and, in the United States at least, we almost all snack, too.

The overwhelming majority of adults in the United States (95.5 percent by one estimate) eat at least one snack every day. Whether you choose a donut or an apple may not depend only on your mood, willpower, or dietary restrictions but also on your sleep — specifically, how many hours you get each night.

New research finds that a consistent lack of sleep may lead to poor snacking habits. To state the obvious, when you are asleep, you are not eating, so more sleep means more time not eating. But the truth of the relationship is more complex.

In a new study, scientists find that people who got seven hours or more sleep ate significantly less sugar, caffeine, and carbohydrates as part of their morning and evening snacks.

Conversely, those who slept less than the recommended seven hours tended to make poorer snacking choices the next day, especially in the earlier and later parts of the day.

The research is published in the Journal of the Academy of Nutrition and Dietetics and will be presented as a poster at the Food & Nutrition Conference & Expo on October 18, 2021.

LONGEVITY HACKS is a regular series from Inverse on the science-backed strategies to live better, healthier, and longer without medicine. Get more in our Hacks index.

WHY ITS A HACK —The study’s focus on snacking and sleep patterns highlights two significant pillars of the two activities’ relationship to one another:

  • Not all snacks are created equal
  • Timing is everything

The idea that not all snacks are created equal is not revolutionary, but the focus on the nutritional quality of snack food is relatively new in the scientific sense.

“When I speak to dietitians at conferences, everyone’s focused on what you eat for breakfast, lunch, and dinner,” the study’s senior author, Chris Taylor, tells Inverse. Taylor is a registered dietician and a professor at Ohio State University.

“The lion’s share of our snacking is coming from what we eat at night.”

As snacks account for 25 percent of the average daily calorie intake, not counting these calories is almost like forgetting about a fourth meal.

“Even if you eat well throughout the day, your snacking can kind of undermine your overall diet quality,” Taylor says. Think about it: 1,000 calories of iceberg lettuce versus 1,000 calories of cookies, he says. Besides that equating to one extreme bowl of lettuce, you would also take in vastly different macronutrients.

Beyond what you are eating to keep you going throughout the day, when you eat seems to play into the choices you make, too, Taylor says. Evening snacks alone bring in more energy and calories than the average breakfast.

“The lion’s share of our snacking is coming from what we eat at night,” Taylor explains.

Americans also tend to drink a lot of their calories in the later hours of the day, whether in the form of soda or alcohol. An April 2021 review suggests alcohol consumption increased through 2020 due to lockdown.

Booze is rich in calories, and drinking can lead to late-night eating, perpetuating a cycle of poor snacking patterns. At the same time, drinking to excess can cause sleep disturbances and poor sleep quality, increasing tiredness the next day.

On the flip side, doing the reverse can create a virtuous cycle: Making a different snack choice can help you sleep better, which in turn may help you make better snack choices the next day. For example, switching out a sweet tea for sparkling water can reduce your sugar intake and give your liver a break from processing sugars, too.

SCIENCE IN ACTION — Nutrition is a relatively new science; the word “vitamin” didn’t exist until 1912. As a result, there is a lot that scientists still don’t know about how the food and drink we consume influences our body and brain health.

“You always hear about the Greek philosophers, but no Greek nutritionist was telling us what to eat,” Taylor says.

One thing we do know is that nutritional quality matters. Consistently consuming foods high in salt, sugar, and fat can cause you to develop high blood sugar, inflammation, and gain weight. Together, these three effects can shape long-term health outcomes.

For the new research, the researchers used data from a national survey of 19,650 U.S. adults aged 20 to 60. Survey participants reported their dietary intake and their sleeping habits on a typical work or school night.

The researchers divided this group into two subgroups based on sleep patterns:

  1. People that slept for seven hours or more on an average night
  2. People that slept for less than seven hours on an average night

The researchers found there were three broad buckets under which most people’s snacking patterns emerged:

  • Morning snacks: Food eaten between meals during the period between 2:00 a.m. and 11:59 a.m.
  • Afternoon snacks: Food consumed between meals during the hours of noon through 5:59 p.m.
  • Evening snacks: Food consumed between meals and eaten between 6 p.m. and 1:59 a.m.

A notable caveat for this study is the time frames for both reports: The survey respondents reported food intake over 24 hours, but they gave several days of sleep data to work out an average over time. The difference between the timing might affect the confidence of the results, Taylor says, but these data can still offer insight into eating habits and the relationship to sleep.

People who slept fewer than seven hours per night tended to snack more often in the morning than people who got a total of seven hours of shut-eye. In turn, these snacks were usually composed of sugary, high-caffeine foods and drinks. The researchers say this may contribute to a higher risk of chronic diseases.

“Intakes of energy, protein, carbohydrate, added sugars, and caffeine from morning and evening snacks were significantly higher for those not meeting sleep recommendations,” the study summary reads.

More than 50 percent of respondents’ non-meal calories came from salty and sweet snacks or sugary beverages. Processed foods are also addictive and keep you reaching for more. Replacing them with healthy fats and whole grains may keep you satiated for longer — both at night and during the following day.

“Sedentary behavior, screen time, and snacking on foods that we love as Americans.”

Interestingly, the results suggest afternoon may be the time you are most likely to make a good snack choice, regardless of your sleep duration. Snacks in the morning tended to be made up of calorie-laden beverages and sweets, while snacks consumed at night tended to be composed of typical snack foods, sweets, and alcoholic drinks.

The results make sense if you think about it. After all, how many of us have had to order a triple-shot vanilla latte or buy a supersized can of energy drink to make it through the 9 a.m. morning meeting after a late one?

HOW THIS AFFECTS LONGEVITY — A less-than-optimal diet can increase the risk of chronic disease throughout the lifespan. It can leave the body in a nourishment deficit — poor nutrition, not just too few or too many calories, can have a complicated and long-lasting effect on the immune system, cognitive function, and more.

The term “beauty sleep” isn’t just cute: Sleep is critical to your body and mind’s health. It helps your body’s cells reproduce and boosts the brain’s long-term memory skills. On the other hand, a lack of sleep is — just like a poor diet — linked to a greater risk of chronic disease.

“As we stay up late, we’re doing all of these things that are also related to obesity: Sedentary behavior, screen time, and snacking on foods that we love as Americans,” Taylor says.

The researchers think taking a more holistic view of your diet can improve your long-term health. They suggest trying intuitive eating instead of crash dieting or other fad eating regimes.

Our favorite part about the new study? Another scientific reason to sleep.

HACK SCORE — 💤💤💤💤💤💤 (6/10 Zzzs for the prioritization of sleep over midnight snacks)

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