What are the 3 main sources of energy in foods?

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.

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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 (1).

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 (2).

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 (2).

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 (2).

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 (2).

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 (3).

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 (3).

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

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 (2, 5).

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.

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 (6).

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 (7).

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 (8, 9).

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 (8, 9).

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 (10).

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 (6).

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.

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 (11, 12).

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 (13).

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 (14).

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 (15, 16).

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 (16).

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 (18).

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 (18, 19).

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 (18, 20).

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.

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.

If you plan it right, what you eat can help keep you healthy and energized all day long. The key is to maintain balanced blood sugar levels and to eat meals made up of low glycemic index carbohydrates combined with protein and small amounts of healthy fats. A well-balanced meal can keep you fueled for as long as four hours, so another pro tip is to eat every four hours or so, to keep a steady flow of energy. The worst foods to eat for sustained energy are high-sugar foods because they cause your blood sugar to quickly rise, triggering the release of too much insulin, which triggers a plunge in blood sugar levels, AKA a sugar crash.

Steady energy feels great. To optimize your daily energy level, try adding some of these foods into your meal plan.

• Oatmeal. The complex carbs in oatmeal mean it’s a slow-burning source of energy. Oats also boost serotonin production which can help us manage stress and enhance learning and memory function. Caveat: sugar-packed packets of flavored instant oats are worth avoiding. Make your own instead and load them up with berries, bananas and a drizzle of maple or honey for a healthy treat of a breakfast.
• Bananas. One of the best foods for energy, whether frozen and blended into a smoothie, sliced onto oatmeal or eaten on the go. They’re full of complex carbohydrates, vitamin B6, potassium and even a little protein. 
• Yogurt. The carbs in yogurt are mainly in the form of simple sugars, such as lactose and galactose. When broken down, these sugars can provide ready-to-use energy. Greek yogurt is an especially good choice. Top with fresh berries and a drizzle of local honey or maple syrup.
• Sesame seeds. Toasted sesame seeds add a little crunch and flavor to salads, soups, stir fries and more. They’re chock full of magnesium, which helps convert sugar into energy, plus they’ve got a blood-sugar-stabilizing dose of healthy fat and fiber.
• Cinnamon. Cinnamon works to keep blood sugar levels stable, therefore it also helps to stabilize your energy levels. One teaspoon of cinnamon contains as many antioxidants as half a cup of blueberries, one of the most antioxidant-rich foods. Shake a little into your yogurt or add a dash to your coffee.
• Water. Dehydration is a certain cause of low energy and even brain fog. Feel a slump? A nice tall glass of cool water might just do the trick. 
• Beans. Whether you opt for pinto, Great Northern, red, black or Anasazi beans, or any of the hundreds of other varieties, they share a similar nutrient profile. They digest slowly, which stabilizes blood sugar. They also contain antioxidants, fiber, protein and carbs. Beans are great sources of folic acid, iron and magnesium, which help produce energy and deliver it to our cells.
• Lentils are tasty little legumes, rich in carbs and fiber. Just one cup of cooked lentils contains about 15 grams of fiber and 36 grams of carbs. Lentils are energy powerhouses, upping your energy levels by replenishing your stores of iron, folate, zinc and manganese. These nutrients help break nutrients down and help with cellular energy production.
• Hummus. Chickpeas in hummus are a good source of complex carbs and fiber, which your body can use for steady energy. The tahini (sesame seed paste) and olive oil in hummus contain healthy fats and slow the absorption of carbs, which helps us avoid blood sugar spikes. 
• Dates are high in natural sugars, so if you need a quick burst of energy mid-day, instead of going for a second cup of coffee go for a handful of dates. Or, if you don't like plain dates, whip up some energy balls or oatmeal bars packed with dates and cinnamon to fight the mid-day slump. Dates contain vitamins and minerals like iron, manganese, copper, potassium and magnesium, in addition to fiber and antioxidants.
• Brown rice is a very nutritious, satisfying food. It’s less processed than white rice which allows it to hang onto more nutritional value in the form of vitamins, fiber and minerals. Just a half-cup of brown rice packs two grams of fiber and lots of your recommended daily intake of manganese, a mineral needed for enzymes to break down carbs and proteins, turning them into energy. It’s also low on the glycemic index, meaning it could help regulate blood sugar levels and promote steady energy levels throughout the day. 
• Avocados. They’re a superfood! Avocados are rich in ‘good’ fats, fiber and B vitamins. Around 85% of the fat in avocados is from monounsaturated and polyunsaturated fatty acids, which promote healthy blood-fat levels and boost the absorption of nutrients. About 80% of the carb content in avocados is made up of fiber, which means delicious, sustained energy.
• Sardines & fatty fish. According to an article from Harvard School of Public Health, fish and other seafood are the major sources of healthful long-chain omega-3 fats and are also rich in other nutrients such as vitamin D and selenium. Fatty fish is high in protein and low in saturated fat. There is also strong evidence that eating fish or taking fish oil is good for your heart and blood vessels. In addition to boosting your energy, eating fish once or twice a week may also reduce the risk of stroke, depression, Alzheimer’s disease and other chronic conditions.
• Eggs are satisfying and packed with protein, which means steady and sustained energy. They also contain leucine, an amino acid known to stimulate energy production in several ways. It helps cells take in more blood sugar, stimulates energy production in the cells and ups the breakdown of fat to produce energy. Eggs are also rich in B vitamins, which help enzymes perform their roles in the process of turning food into energy.
• Shrimp. These versatile little critters are low in calories and offer nice helpings of vitamin B12 and omega-3 fat, a known mood and energy booster. 
• Cashews are low in sugar and rich in fiber, heart-healthy fats, and plant protein. They're a solid source of copper, magnesium and manganese which are key ingredients for energy production, healthy bones brain health and immunity.
• Sweet potatoes are a great source of iron, magnesium and vitamin C, a nutrient needed for energy production. Add to that a healthy dose of fiber (complex carbs) and these nutritional powerhouses are also rocket boosters for your energy level.

To learn more about nutrition, exercise and health and wellness topics, visit the INTEGRIS Health For You blog.