You would’ve heard it all – eat every 2-3 hours, don’t have too much caffeine, keep hydrated, eat healthy, and so on.

But do you know that certain types of food, which also happen to be the most regularly consumed by students, can send your energy level soaring to the top of the rollercoaster, and in short time, to its lowest point. And this crash can deprive you of the much needed energy to focus on the task at hand, including studying, something you can prevent by a better choice of what you eat or drink.

Imagine, this happening during an important day, say the day you’re taking an important test or the day you really need to slog at high efficiency to pull off that last-minute submission.

Therefore, you need to be more intentional about what food to eat when studying, at least for important occasions.

Let’s take a brief detour to understand the simple science behind how different types of foods affect our energy levels. Trust me, it’ll help you understand this post better, and even drop some smart words when explaining the same to your classmates.

What is Glycemic Index and what does it tell about best foods for studying?

Your body gets its dose of energy primarily from carbohydrates when, during digestion, they release glucose into the bloodstream. Glucose is like the gasoline in a car, the fuel for our body which keeps our brain awake and alert. Foods which release glucose rapidly, spike up energy level quickly followed by an equally quick drop, leaving you jaded earlier than foods which release glucose slowly.

How quickly a food releases glucose in bloodstream is measured by an index called Glycemic Index (GI). Foods that break down quickly during digestion and release glucose rapidly into the bloodstream tend to have a high GI. Pure glucose has the highest GI of 100, and other food items are benchmarked against it.

Common food items and their GI

Low GI (0-55)

Fructose; beans (white, black, pink, kidney, lentil, soy, almond, peanut, walnut, chickpea); small seeds (sunflower, flax, pumpkin, poppy, sesame, hemp); most whole intact grains (durum/ spelt/ kamut wheat, millet, oat, rye, rice, barley); most vegetables, most sweet fruits (peaches, strawberries, mangos); mushrooms

Medium GI (56-69)

White sugar or sucrose, not intact whole wheat or enriched wheat, pita bread, basmati rice, unpeeled boiled potato, grape juice, raisins, prunes, pumpernickel bread, cranberry juice, regular ice cream, banana

High GI (70-100)

Glucose (dextrose, grape sugar), high fructose corn syrup, white bread (only wheat endosperm), most white rice (only rice endosperm), corn flakes, extruded breakfast cereals, maltose, sweet potato (70), white potato (83), pretzels, bagels

Source: Wikipedia

And here is an illustrative list of common meals/ snacks that you may eat (or not eat) to have better energy levels when studying:

What to eat when studying:

These are largely Low-GI foods: wholegrain sandwiches, oats, porridge, low-sugar museli, low-sugar energy bars, yogurt with seeds/ nuts, egg with wholegrain bread, low-fat dairy, soups, salads, and most fruits.

What not to eat when studying:

These are largely High-GI foods: pizza, white bread, burger, cake, chocolate, cookie, ice cream, potato chips, and sugary beverages.

How glucose level changes after eating a meal?

This graph illustrates how your glucose level, and hence energy level, changes after two different types of meals – low- and high-GI.Variation of blood glucose level with food type

Two inferences can be drawn from this graph:

Inference # 1

If you eat food with high GI (see note in the next para for exceptions), your energy levels will rise quickly and then fall equally quickly leaving less supply of glucose to the brain resulting in lack of focus, fatigue, and drowsiness.

Note: In practice, some food items with high GI may not release much glucose to make an impact on your energy levels because of their low carbohydrate content in a normal serving. For example, watermelon, with a GI of 72, falls in high-GI category, but its carbohydrate content is so low (5g in a 100g serving, most of rest being water) that it barely moves the glucose needle.

Inference # 2

Another thing you’ll notice in the above graph is that your energy levels go down in 2-3 hours irrespective of what GI food you eat, which implies that you need to replenish your glucose level after every three hours, if not two, in order to maintain your energy level.

Best eating practices when studying: summary

  • Now, low-GI food, largely, is also healthier than high-GI food. And healthier options, like most good habits, are painful to adopt. The best option, of course, is to have high proportion of low-GI food in your diet, but if you can’t resist the temptation of cookies and sugary snacks, have higher proportion of low-GI food at least before and during your most important sessions of the day. That way, you’ll maintain a higher level of energy when it matters the most.
  • A corollary: on important days such as exam day or days when you’ve to handle tight deadlines requiring high-intensity work for long hours, you should ideally stick to a low-GI plan through the day interspersed with some medium-GI stuff such as banana to give booster shots.
  • When studying, eat small, nutritious meals every three hours or so to maintain your energy level. Besides, if you eat after long gaps (5-6 hours), you tend to eat larger quantities, which leaves you drowsy as more blood flows to the stomach to digest the larger quantity. (If your diet includes healthy proportion of protein, you’ll have lesser craving for food, as protein is more filling – and takes longer time to digest – than carbohydrate or fat.)

How you can change your habit, that is increase your intake of low-GI food?

It’s not easy to switch to a low-GI diet, as it’s also often the healthier, less-tastier option. You need to take conscious steps in making that change. Specifically:

  • You can make the biggest dent in your habit by making low-GI food more accessible. If you don’t have the healthy stuff within your reach, you’ll invariably head to the nearest vending machine and fall to chips and soda.

    So, when going to school or college, you got to stuff some healthy snacks such as wholegrain crackers, high-fibre less-sugary cereal bars, fruits, and dry fruits in your bag. In fact, non-perishable items can find a permanent place in your bag and you don’t need to stuff them every day.

  • If you’re living in a dorm and if you’ve access to a microwave, you can store items such as oatmeal. And if you dine out, you can go for healthier options such as salads, wraps, and grilled foods. This option, naturally, requires resisting peer pressure and inertia, and hence is tougher (to execute) than the first.


What you eat can impact your academic (or other) performance? If you’ve low-GI food in your diet, you’ll have more balanced energy level through the day, which will make you more alert and focused, and less tired.

However, despite its obvious benefits, you may not be able to sustain a low-GI heavy diet. But you can certainly do it on important days – exam days or days which require high-intensity work over long hours, and make it count when it matters the most.

Question: What are the best foods and eating habits that have worked for you when studying?