The foods you eat supply your body with the energy it needs, specifically calories and complex carbs. A diet rich in complex carbs may help you avoid energy crashes during the day.

Along with exercising, hydrating, and getting enough sleep, the foods you eat play an essential role in keeping your energy levels high.

As such, you may wonder which foods may help maintain your alertness and focus throughout the day.

This article explains whether certain foods can boost your energy levels.Toma Evsuvdo/Stocksy United

How do certain foods affect your energy levels?

The first thing you need to know is that all foods give you energy in the form of calories, which are a measure of energy.

One calorie measures the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius (1Trusted Source).

That said, not all foods affect your energy levels the same way.

Of the three macronutrients, carbohydrates provide a faster energy source compared with proteins and fats, as they’re your body’s preferred source of energy (2Trusted Source).

Nevertheless, carbs are categorized as simple and complex, as well as having a high or low glycemic index (GI). And once again, they affect your energy levels differently.

Simple vs. complex carbs

Simple carbs comprise either one or two sugar molecules, and they’re known as either monosaccharides and disaccharides, respectively. Because their structure is so small, they’re easier to digest and thus easily used for energy.

However, their fast digestion rate means that they cause a rapid rise in your blood sugar levels — and consequently your energy levels — which is usually followed by a crash that may leave you feeling sluggish (2Trusted Source).

Some examples of simple carbs you might want to limit to avoid such an effect include white bread, breakfast cereals, candy, fruit juice, and processed or refined grains with added sugars.

On the contrary, complex carbs comprise three or more sugar molecules and are known as oligosaccharides and polysaccharides (2Trusted Source).

Since their structure is more complex and they’re usually fiber-rich, they take longer to digest and thus provide a gradual increase in your blood sugar levels (2Trusted Source).

This means that complex carbs provide you with a steady supply of energy throughout the day.

Examples of complex-carb food sources you could try to include in your diet include unrefined whole grains, oats, legumes, and starches.

Glycemic index

Another way to determine how carbs may affect your energy levels is through their glycemic index, which tells you how a carb-containing food may affect your blood sugar levels (3Trusted Source).

Foods with a high GI tend to spike and then crash your blood sugar levels, much like simple carbs. In contrast, foods with a low GI — like complex carbs — aren’t known to cause abrupt variations in your blood sugar levels (3Trusted Source).

Research shows that high GI diets, which are high in sugars and low in fiber, are associated with reduced alertness and increased sleepiness (4Trusted Source).

The GI of foods may be especially relevant in the case of whole fruit and dairy.

Structurally, the carbs in fruit and dairy — fructose and lactose, respectively — are simple. Yet, they’re both nutrient rich, low GI foods that may provide a quick energy source without sacrificing your diet quality (2Trusted Source, 5Trusted Source).

Nevertheless, keep in mind that fruit juices and flavored dairy products tend to have added sugars, and therefore a high GI.

Summary

Carbs provide a faster energy source compared with proteins and fats. Simple or high GI carbs tend to spike and then crash your energy levels. Complex or low GI carbs ensure a steady energy supply throughout the day.

What about caffeinated foods?

Caffeine is the most widely consumed stimulant in the world. Though it has many benefits and uses, it’s primarily sought after to help combat fatigue and drowsiness (6Trusted Source).

Caffeine-containing foods and beverages such as coffee, tea, caffeinated sodas, energy drinks, matcha, chocolate, guarana, and yerba mate may also help reduce symptoms of fatigue and improve alertness and vigilance (7Trusted Source).

This effect is primarily due to caffeine’s effect on your brain, which acts by blocking adenosine receptors, leading to increased releases of dopamine and noradrenaline (8Trusted Source, 9Trusted Source).

Adenosine is a compound with sleep-promoting effects, while dopamine and noradrenaline are two chemical substances that stimulate your heart and central nervous system, thus increasing alertness and focus (8Trusted Source, 9Trusted Source).

Nevertheless, be mindful about the type of caffeinated products you choose. Some of them, such as energy drinks and caffeinated sodas, tend to be high in added sugars, which may increase the risk of obesity, type 2 diabetes, and heart disease (10Trusted Source).

Plus, while caffeine intake is generally recognized as safe, some people may experience side effects upon caffeine consumption, with symptoms ranging from mild to severe. Symptoms may include anxiety, restlessness, insomnia, irregular heart rate, and tremors (6Trusted Source).

Summary

Caffeine-containing foods and beverages may also help reduce fatigue and improve alertness. However, while caffeine is generally recognized as safe, some people may experience mild to severe side effects.

Don’t forget about exercise, hydration, and sleep

Exercising, hydrating, and getting enough sleep are also key to increasing your energy levels.

Aim to meet physical activity recommendations

Research shows that meeting physical activity recommendations is associated with improved energy and reduced fatigue, even when leading an otherwise sedentary lifestyle (11Trusted Source, 12Trusted Source).

In fact, exercise is often recommended as part of the treatment for chronic fatigue syndrome — a condition characterized by long‐lasting fatigue, joint pain, headaches, sleep problems, poor concentration, and short‐term memory problems (13Trusted Source).

Current Physical Activity Guidelines for Americans recommend that adults get 150–500 minutes (2.5–5 hours) of moderate intensity aerobic physical activity per week, such as jogging, dancing, swimming, and biking (14Trusted Source).

If you’re currently physically inactive, consider starting with lower intensity activities and gradually increasing the frequency and duration of your workouts.

Strive to stay properly hydrated

Hydrating properly during the day could give you an energy boost and help fight feelings of fatigue.

Not drinking enough water may lead to dehydration. Mild to moderate dehydration may result in difficulty concentrating, headaches, irritability, lethargy, and sleepiness (15Trusted Source, 16Trusted Source).

According to the Institute of Medicine, men need about 15.5 cups (3.7 liters) of water per day, while women need 11.5 cups (2.7 liters) a day. However, your needs may change depending upon the climate and your physical activity levels (16Trusted Source).

One easy way to stay on top of your hydration status is by monitoring your urine color. A clear or pale color is a good indicator of optimal hydration (17).

Get ample sleep

Sleep health deserves the same level of attention as exercise and diet when it comes to energy levels and general health (18Trusted Source).

Your body needs sleep for energy restoration and conservation. Thus, sleep deprivation caused by inadequate sleep leads to decreased alertness, performance, and an overall deterioration in health (18Trusted Source, 19Trusted Source).

Unfortunately, poor sleep health is a common denominator in today’s overworked and overstimulated society, with roughly a third of Americans sleeping less than the recommended 7 hours for adults ages 18–60 (18Trusted Source, 20Trusted Source).

Adequate sleep will not only improve your energy levels but also potentially your overall health and quality of life.

Summary

Staying on top of your physical activity levels, hydration, and sleep will also help reduce tiredness and keep you feeling energized during the day.

The bottom line

While all foods provide energy, eating a wholesome diet rich in complex carbs may be the best way to avoid energy crashes throughout the day.

In addition, be sure to accompany a well-balanced diet with enough exercise, hydration, and ample sleep to improve your energy levels and reduce fatigue.

Nevertheless, consider talking with a healthcare professional if you’re experiencing serious or prolonged fatigue.