Eat to Boost Mental Alertness

The right diet can help keep you on your game

By Star Lawrence
WebMD Weight Loss Clinic - Feature

Reviewed By Charlotte E. Grayson, MD

Do you drag through the day, plodding through your tasks with barely an original thought, much less a creative brainstorm? Whatever happened to mental alertness -- that zippy, observant, "on top of it" feeling?

Some experts believe your diet -- what you eat and how much -- plays a big role in your mental alertness.

Mental alertness can be especially important for schools that depend on their students' achievement test scores for more funding. One researcher -- David N. Figlio, PhD, Knight-Ridder professor of economics at the University of Florida in Gainesville -- believes some schools try to get an edge by boosting carbohydrates and calories in their lunch menus on test days.

To prove his theory, Figlio looked at 23 school districts in Virginia, and found that those schools most likely to hike calories on test days were in districts where funding was threatened by bad test performance. On average, the lunches served on test days had 863 calories, up from 761 calories before the tests and 745 afterward. Indeed, test scores in those districts did rise, by 6-11%.

Though Figlio admits this is a small study, he says it's clear that by serving corn dogs instead of regular hot dogs, along with higher-calorie desserts and higher-carb pizza, school lunch workers were giving the kids more sugars and simple carbs on test days.

"Carbohydrate boosts last a reasonable amount of time," Figlio tells WebMD. "Certainly the 90 minutes to a few hours it takes to test."

His conclusion: "Food matters. Even lousy food can give a short-term brain boost."

And if it works in kids, why not in adults, too?

Can Carbs Boost Brainpower?

Not so fast, says Judith Wurtman, PhD, director of a women's health program at the MIT Clinical Research Center in Boston. Few studies have been done on the various parts of the diet and how they affect children's mental alertness, she says: "We don't have data on whether kids do better on sardines or chocolate. Most of the studies are on eating versus going into class or a test without eating."

Ruth Kava, PhD, RD, director of nutrition at the American Council on Science and Health in New York, is also skeptical that it's the extra carbohydrates or calories that would increase performance and boost mental alertness. "I haven't seen this report, but maybe the kids weren't eating at all, and anything improved their performance," she tells WebMD. "We do know nourishment improves brain function."

At least chemically speaking, carbs aren't the key to mental alertness, Wurtman tells WebMD. She explains that two brain chemicals, epinephrine and dopamine, govern mental alertness. These chemicals are made from an amino acid called tyrosine. If you're engaged in sustained mental activity, you need to replace the tyrosine -- and it comes from proteins, not carbs. "You don't need much, two to three ounces," she says.

"If you consume protein before a task, you can make sure whatever brainpower you, or your child, had going in is still there at the end of the task. Carbs do not really have an effect on mental alertness," Wurtman says.

But, according to Wurtman, eating more calories or glucose could end up helping people concentrate to a certain degree by calming them down. That extra crust in the deep-dish pizza may help your body make more serotonin, the feel-good brain chemical that calms you.

So "if someone is tapping their foot next to you, you may be able to tune it out," Wurtzman says. "Serotonin keeps anxiety from interfering with mental alertness."


"How about coffee for mental alertness? Coffee has been shown to increase reaction time"

So what have we learned?

  • To increase your own (or your child's) mental alertness, eating enough is important. "Not too much, though," says Kava. "Too much makes you sluggish; all the blood rushes to your digestive tract."
  • Protein is key, as it provides sustained fuel to the brain.
  • Carbohydrates can center you and help you resist distractions.
  • And fat? "If you eat a lot of fat and try to think, you can't," Wurtman says. Studies show that eating fat can cause fatigue.

Mental Alertness Foods

If you're looking to boost your mental alertness in the morning, it's a good idea to include these foods in your breakfast, Wurtman says:

  • Low-fat cottage cheese
  • Yogurt
  • Scrambled eggs, with both the yolks and whites
  • Veggie burgers
  • Peanut butter
  • Whole-grain toast
  • Hot cereal, cold cereal, English muffins (as long as you eat them along with some protein)