Advertising would have you believe that a big bowl of sugary cereal or a syrupy iced coffee drink will make you bright-eyed and bushy-tailed in the morning.

But that sort of sugar-laden breakfast may be one of the worst things you can do to help you wake up alert and refreshed.

A major new sleep study shows a breakfast rich in complex carbohydrates — think a big bowl of steel-cut oatmeal, with some strawberries for flavor — is key to waking up without feeling sluggish.

“We found that when you have spike in your blood glucose after breakfast, you’re going to feel less alert, you’re going to feel more sleepy after that breakfast,” said lead researcher Raphael Vallat, a postdoctoral fellow at University of California, Berkeley’s Center for Human Sleep Science. “You want to avoid foods that will drastically increase your blood glucose.”

Actually, a good breakfast is only one part of a three-step prescription for avoiding morning grogginess, Vallat and his team reported recently in the journal Nature Communications.

People who want to wake up alert also should get more than their usual amount of physical activity the day before, Vallat said, and they should sleep a little longer into the morning.

“If you wake up later than usual, you’re going to feel a little more alert,” Vallat explained.

These recommendations are based on a study of 833 people who wore activity trackers over a two-week period to record their sleep patterns and levels of exercise.

These folks also were given a variety of prepared breakfasts to eat, so researchers could see how different types of nutrients would affect their wakefulness.

The study group included 340 identical twins and 134 non-identical twins, who were compared against 359 non-twins to see if genetics played a role in morning wakefulness.

The study is important because these people were observed going through their day as usual rather than being studied in a sleep lab, Vallat said.

“Most of the studies that have looked at how you wake up, how alert you feel in the morning, they’re usually done in a sleep lab,” Vallat said. “But that’s not like the real world. For me, it’s very important to have this kind of real-world condition.”

Morning grogginess isn’t just a drag or a nuisance, but can be dangerous, said senior researcher Matthew Walker, a professor of neuroscience and psychology at UC Berkeley.

“We know that there are numerous auto accidents and job injuries that will occur tomorrow, that did occur today, because people were unable to effectively wake up,” Walker said.

Each of three factors identified by the researchers — a complex carb-heavy breakfast, more exercise and waking later after at least 7 to 9 hours of sleep — independently improved the participants’ wakefulness.

On the other hand, genetics played only a minor role in next-day alertness, explaining only about 25% of differences between individuals, researchers found.

“There are some very basic and achievable things you can start doing today and tonight to change how you awake each morning,” Walker said.

Researchers think that waking a little bit later places people on the upswing of their 24-hour circadian rhythm, essentially getting a natural boost from the process that ramps up your alertness throughout the morning.

But one expert noted that might not be practical.

“Sleeping more and/or later than typical might lead to improved morning alertness, but typical sleep recommendations suggest that people should generally stay on as stable a schedule for sleep as they can,” said Dr. Douglas Kirsch, medical director of sleep medicine at Atrium Health in Charlotte, N.C. “Practically, it is impossible to sleep later than you usually do every day, but this data might be a useful tool on a day when morning alertness is particularly important.”

As far as physical activity goes, the more the better.

“We found essentially a linear association,” Vallat said. “The more physical activity you do on the day before, the more alert you’re going to feel and the easier it’s going to be to wake up the next morning.”

However, keep in mind that what constitutes more exercise and longer, later sleep will vary from person to person, Walker said.

“What’s specific here is specific to you, the individual,” Walker said. “If you get more exercise the day before than you would typically get and if you sleep longer and later into the next day than you would typically sleep, that’s where we see this traction. That’s where we see the best kind of punch for the pound, as it were, in terms of improving your ability to wake up.”

The type of breakfast you need for wakefulness also will vary a bit, generally based on how it affects your personal blood sugar levels, researchers said.

Even the type of complex carbohydrate you have for breakfast matters, Walker said.

For example, steel-cut oats should be better for wakefulness than flat-rolled oats, because “steel-cut oats will provide a slower release of carbohydrate and therefore a more manageable blood sugar response,” Walker said.

Other examples of slow-release complex carb foods include sweet potatoes, brown rice and quinoa, he said.

Interestingly, the second-worst wake-up came from a high-protein breakfast involving a big morning shake containing 40 grams of whey protein, Vallat said.

“To be honest, that was kind of surprising to me,” Vallat said. “I think it’s still fine to eat some moderate amount of protein, but what you want to avoid is an excessively high amount of protein for breakfast because this seems to reduce your alertness.”

To put it in context, a lumberjack breakfast of three eggs and four slices of bacon contains about 30 grams of protein.

Not all sleep doctors buy into these findings, however.

“I agree that prior night’s sleep, previous day’s exercise, both will affect your level of alertness,” said Michael Breus, a clinical psychologist who guided the launch of “I think the breakfast portion of the study was a little off. What I mean by this is simple — very few people wake up and eat quickly.

“And they are suggesting a high-carb breakfast. In my experience and if you look in the literature you will see that carbs make people sleepy. This is because of the rise in serotonin,” Breus continued.

Breus’ recommendations for waking up refreshed are simple and direct:

  • Wake the same time every day.
  • Stop caffeine by 2 p.m.
  • Stop alcohol 3 hours before bed.
  • Exercise daily, but more than 4 hours before bed.
  • Upon waking, take 15 deep breaths, drink 15 ounces of water, and go outside to get 15 minutes of sunlight.

More information

The U.S. National Institute on Aging has more tips for getting a good night’s sleep.

SOURCES: Raphael Vallat, PhD, postdoctoral fellow, University of California-Berkeley’s Center for Human Sleep Science; Matthew Walker, professor, neuroscience and psychology, University of California, Berkeley; Michael Breus, PhD, clinical psychologist,; Douglas Kirsch, MD, medical director, sleep medicine, Atrium Health, Charlotte, N.C.; Nature Communications, Nov. 19, 2022