How to improve your energy levels through diet

If you’re looking for foods that will increase your energy levels, unfortunately, there isn't a simple answer.

Calories are a measure of energy, so technically, all foods with calories provide energy. 

But, as ZOE co-founder Prof. Tim Spector discusses in his book Spoon-Fed, "Although we can accurately measure the calorific value of a meal, the relationship between those calories and our body is much less straightforward."

Different foods will affect your energy in different ways, depending on their nutritional content and how your body responds to them.

ZOE's PREDICT program is the largest nutrition science study in the world. We’ve measured over 40,000 participants' blood glucose and blood fat levels after eating. The results showed that even identical twins have different responses to the same foods.

In this article, we’ll explore how food influences how energized you feel.

While there’s no universal advice, we’ll look at how different types of food could provide the energy you’re after.

Energy sources and energy levels

To explore how foods give you energy, let’s start by looking at carbohydrates, fats, and protein, the macronutrients in food. 

Carbohydrates, or carbs, are your body’s primary source of energy. When you eat carbs, your body breaks them down into individual sugar molecules. These sugars then enter your bloodstream, and your cells use them for energy. 

Fats are the most energy-dense macronutrient. Compared with a gram of carbohydrates or protein, each gram of fat contains more than twice as much energy. Nearly all of the fat you eat is in the form of triglycerides, which are also released into your bloodstream for energy. 

Protein plays an important role in the function of your muscles and tissues. In this way, it also prevents fatigue. Your body can use protein for energy, although it’s not an efficient source. 

All three macronutrients can provide energy. But carbs give your body access to the energy more quickly. 

While foods provide energy for the cells in your body, they don’t necessarily have the same effect on how energized you actually feel. 

For example, certain foods can cause large spikes in blood sugar. For some, but not all people, this can result in a dip in blood sugar 2–4 hours afterward. 

Although increases in blood sugar are normal, big swings can lead to lower energy levels, as well as other symptoms, like hunger and difficulty focusing. So, preventing large fluctuations in your blood sugar can help improve your overall energy levels.

Eating for your unique biology can increase your energy. Our unpublished data found that 82% of people who followed their personalized ZOE plan for 3 months said their energy levels increased.

With this in mind, let's look at how certain foods tend to impact energy levels. Remember, these are general guidelines. The end result may vary, based on your body.

Foods with complex carbohydrates

Carbohydrates are your body’s preferred energy source — but not all carbs are the same.

Simple carbs are just one or two sugar molecules linked together, so your body can break them down and send them to your bloodstream quickly. Eating simple carbs and starches can give you a quick burst of energy, but you’re more likely to experience those sugar dips afterward.

Complex carbs, on the other hand, have more sugar molecules. They also have more fiber than simple carbs, so they take longer to break down. Because of this, the sugars enter your bloodstream more gradually, so you have a steadier and longer-lasting supply of energy.

Some sources of complex carbohydrates, which can help you maintain energy throughout the day, include:

  • vegetables, such as broccoli, spinach, sweet potatoes, butternut squash, and corn

  • whole grains, such as oatmeal, bulgur wheat, pearl barley, quinoa, and buckwheat

  • fruits, like apples, strawberries, raspberries, and peaches

  • legumes, such as black beans, chickpeas, and lentils

  • nuts and seeds, especially cashews, pistachios, pumpkin seeds, and pine nuts

Complex carbs take longer to break down than simple carbs, but ultimately, the way your body responds to carbs is unique. 

Foods with fiber

Fiber is a type of carbohydrate that your body can’t actually digest. However, fiber helps slow the rate that sugars are released into your bloodstream.

Pairing your carbs with fiber, protein, and fat helps prevent big swings in blood sugar that lead to generally lower levels of energy. Plant foods tend to have plenty of both complex carbs and fiber.

Some good sources of fiber include:

  • green peas

  • broccoli

  • Brussels sprouts

  • sweet corn

  • carrots

  • avocados 

Foods with healthy fats

Fats are an energy-dense nutrient, and the body absorbs and digests fats much slower than carbohydrates. 

Fats are more energy dense than carbohydrates or protein. They're essential for the body to function at its best, for providing energy, and for delivering fat-soluble nutrients, such as vitamins A, D, E, and K. 

As fats take longer to digest than simple carbohydrates, pairing them with a simple carbohydrate source can slow your blood sugar response

This can help prevent the large swings in blood sugar that lead to energy crashes and lethargy. 

Sources of healthy fats include:

  • avocados

  • nuts, such as almonds and cashews

  • seeds

  • oily fish, such as trout and mackerel

  • extra virgin olive oil

Foods with protein

Your body uses most protein to build and repair cells so your muscles and tissues can work properly. This helps prevent fatigue. 

Protein can be a source of energy, but it’s not a very efficient one. Still, like fat, protein takes longer to digest than carbs. 

Pairing protein with complex carbs slows the release of energy. It’s a great way to keep you feeling full for longer and maintain a slow release of energy throughout the day.

Good sources of protein include:

  • beans

  • eggs

  • nuts and seeds

  • legumes

  • dairy

  • fish

  • tofu

Gut-friendly foods

Looking after your gut health by eating gut-friendly foods can directly affect your energy levels.

Dr. Will Bulsiewicz, ZOE’s U.S. medical director, who is also a board-certified gastroenterologist and the New York Times bestselling author of Fiber Fueled, explains: 

“The most basic and most essential function of our gut is the digestion of our food. This includes the breakdown of ingested food, absorption of nutrients, and elimination of waste. When things are working properly, things are effortless and in rhythm.”

But when they aren’t working, fatigue is often one symptom.

The good news is that Dr. B says increased energy is one of the first symptoms of improved gut health that he sees in his patients.

Studies also link a healthy gut microbiome to better sleep, a big factor in energy levels.

You can improve your gut health by:

  • eating foods rich in probiotics, such as live yogurt, miso, kimchi, kombucha, kefir, and sauerkraut

  • eating foods rich in prebiotic fiber, such as legumes, onions, garlic, mushrooms, asparagus, and whole grains 

  • aiming to eat a variety of at least 30 different plants each week (this includes nuts, seeds, spices, and herbs)

  • including colorful foods packed with polyphenols, such as blueberries, black olives, and red onions

  • limiting ultra-processed foods that are low in nutrients and fiber

Quick energy boosters

If you’re looking for a fast way to feel more energetic, try snacks that combine carbs with protein, fat, or both. 

For example:

  • carrots and hummus

  • apples and peanut butter

  • avocado and wholegrain bread

  • yogurt and fruit

Foods to eat less often

We've talked a lot about which foods to eat regularly, so let's look at a few foods to eat less often. Ultra-processed foods and processed simple carbohydrates fall into the second category. 

While these foods have sugar, it’s not the naturally occurring type in plant foods, like fruits. Manufacturers add sugars to these foods during processing.

These added sugars provide fewer nutrients that benefit your overall health. They also tend to displace nutrient-dense foods in your diet. 

Foods with added sugar may offer a short-term energy boost, but they can lead to a crash later. Also, they don’t offer the same long-term benefits as healthier, nutrient-dense alternatives.

If you want to improve your energy levels, you may want to limit foods with added sugar, like:

  • soda

  • foods and drinks that contain corn syrup

  • cookies, cakes, and brownies

  • high-sugar breakfast cereals

  • ice cream


When it comes to energy levels and food, the calorie count doesn’t tell the whole story. In fact, it shows us very little about how the food will affect our body.

As a rule of thumb, sticking to whole foods is a good place to start when you’re looking to improve your energy levels. Try to opt for nutrient-dense, unprocessed whole foods.

Foods with complex carbohydrates are longer-lasting sources of energy than those with simple carbs. 

Adding foods that contain fiber, protein, and healthy fats to your diet can also help keep your blood sugar levels stable.

And supporting your gut health can help you feel your best. Eating a variety of plant foods is great for your gut. Aim for at least 30 different plants each week. 

Your body is unique, and the best foods to give you energy are personal to you. 

The ZOE at-home test analyzes your unique blood sugar and blood fat responses to food. Along with a breakdown of your gut microbiome, we use this information to help you find the best way to eat for your body.

To get started, take our free quiz.


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Physiology, carbohydrates. StatPearls. (2022).