What Food to Avoid Before an Exam? The Complete List

If you really think that your diet doesn't affect performance, then you clearly haven't been eating your blueberries.

Most schools, colleges and universities differ greatly. However, there are a few things that almost all educational enterprises have in common.

One of these things is testing. Whether it be weekly quizzes, midterm and final exams or both, teachers need to know how much their students have mastered. Often, quizzes and exams are the biggest piece of a student’s overall grade.

This means that tests can be stressful, terrifying and even nightmare-inducing. So how can students make sure that they are in top shape for these all-important tests?

Studying hard, sleeping well, and leaving time for exercise are all great for improving test results. However, one thing that many students don’t consider on or before test day is their diet. What you eat, how much you eat, and when you eat can make the difference between a passing score and a perfect exam. Here’s a list of food to avoid before an exam:

How to Stay Functioning

To stay functioning at 100 percent throughout the duration of a quiz, exam, or test, it’s vital for a student’s brain to be alert, healthy, and primed for memorization. Even if a student doesn’t sleep enough the night before a test, certain foods and drinks can make up for a sleep deficit.

Four of the best foods for brain health and memory are blueberries, wild salmon, avocados, and walnuts. Blueberries have been called a “superfood” due to their youth-preserving antioxidants, which neutralize potentially disease-causing “free radical” molecules in the body.

They have also been shown to slow brain aging and help prevent neurodegenerative diseases. Basically, if you want your brain to stay elastic, youthful, and strong not only for your student years but far into the future, adding blueberries to your diet is a good way to go.

Walnuts, avocados, and salmon are all rich in omega-3 fats. According to the University of Maryland Medical Center, these fats have been shown to reduce risks for cancer, heart disease, and arthritis, as well as be very good for memory, concentration, and overall brain function.

Because the human body cannot produce omega-3 fatty acids, it is essential to eat foods that contain this important nutrient. By eating walnuts, salmon, mackerel, or other foods rich in omega-3 fatty acids on the days leading up to an important exam, a student can prime their brain for concentration and memorization.

Although it may be tempting to eat a load of carbohydrates on or before a big test, it’s inadvisable. Carbohydrates provide a quick energy boost and can provide a short-term memory boost, but, in the long run, eating foods such as bread, candy, bagels, rice or pastries will slow down brain function.

When a person eats carbohydrates, it leads to the release of the neurotransmitter serotonin. Serotonin is involved in body processes such as sleepiness and pain sensitivity. By eating a load of carbs before a test, a student will lower their brain function and risk the onset of sleepiness after the initial energy boost wears off. Not so good for test day.

Instead of eating carbs, there are other foods and drinks that boost your energy while leaving alertness intact. Of course, coffee is the best-known drink for increasing energy.

According to statistics on the Harvard University website, 54% of Americans age eighteen or over drink coffee every single day. But some people are sensitive to caffeine or don’t find coffee to their taste. For these people, there are alternatives.

One alternative is freshly brewed or bagged green tea. Like coffee, it contains vital antioxidants, and boosts alertness and concentration. Because green tea typically contains less caffeine than coffee, it can be a good option for people with caffeine sensitivity. Drinking green tea the morning before a test can boost concentration, alertness and overall productivity. In addition to that, green tea can decrease a person’s risk for many different types of cancer. Really, there’s no reason not to drink it.

Another food rich in antioxidants and useful for providing an energy boost is dark chocolate. Since chocolate contains caffeine, consuming it can lead to increased productivity and alertness, as well as elevated moods. Remember, though, that this chocolate must be dark to count as part of a healthy, balanced diet.

Milk chocolate, or desserts containing high levels of refined and non-natural sugars, will do more harm than good. Chocolate milk, while great as an after-workout treat, is not what you should be drinking on or before exam day. The last thing a student needs is for their “sugar high” to wear off mid-exam, leaving them lethargic and unmotivated.

Unlike carbs, proteins do not lead to the release of serotonin. In fact, foods rich in proteins — such as egg yolks, lean chicken, and yogurt — have all been shown to boost energy levels and brain function without causing sleepiness.

Having an omelet, fried egg, bowl of yogurt, or sliced chicken with your blueberries and green tea can greatly improve brain function and energy levels. In addition to high levels of protein, yogurt also contains highly beneficial “good” probiotics, tiny microbes that aid in various vital body functions.

If you want to feel your best, you might want to consider taking a probiotic formula that can help balance your intestinal environment — this, in turn, will help alleviate digestive issues, brain fog, joint pain, and sweet cravings while allowing you to build a strong stomach.

With all these brain-healthy nutrients, alertness-boosting sources of caffeine and disease-preventing antioxidants to choose from, the question is: What are some of the best combinations of foods to eat the morning before a big test?

Well, a balanced breakfast consists of protein, dairy, grains, and fruit, and/or vegetables. One meal that fulfills all these category requirements is a smoked salmon omelet with a bowl of fruit or nuts (blueberries and walnuts, especially) and a slice of whole-grain toast – everything contrary to that is considered a food you should avoid before an exam.

Although toast contains carbohydrates, the omega-3 acids in whole-grain wheat makes up for the potentially sleep-inducing effects. If only a slice or even a half a slice is consumed, you should be perfectly fine. And if you spread your toast with non-sweetened peanut butter, the extra protein and omega-3 fats can boost brain power as well.

Another option is a bowl of oatmeal with blueberries, accompanied by a fried or scrambled egg and sliced avocado on toast. Either that, or you can dip sliced avocado in balsamic vinaigrette for a delicious and brain-healthy snack or side dish.

Of course, eating too much of anything is never a good idea. And eating a large meal directly before a test, regardless of what the meal contains, may lead to sleepiness and loss of motivation as the body’s energy is channeled into digestive efforts.

If an exam or test is in the morning, if you plan on eating a big meal, make sure to eat at least a half-hour to an hour before the test begins. If, by the time the test begins, your energy levels are dipping, carry a few squares of dark chocolate with you to eat right before the exam begins.

Though it might be tempting to have a big glass of juice or a cap of chocolate milk, remember that sugar highs — a common effect of juice or chocolate milk consumption — will leave you more tired and unmotivated when they (quickly) wear off, and that’s why those are the foods to avoid before an exam. It’s better to have a tall glass of water and/or a cup of green tea or coffee than to risk losing your sugar high mid-test.

Devon Hodge, Western Washington University

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Devon Hodge

Western Washington University


  1. […] Eating is very important, but it is very important to eat a nutritious meal, not one filled with sugar. Also overloading carbs can slow brain function making it harder to comprehend the test. Some of the best brain foods before tests are blueberries, wild salmon, avocados and walnuts. These foods are great to help improve your focus and make sure your stomach is full. For more on eating for test success, click here. […]

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