(Illustrations by Luciano Cian for USC Dornsife Magazine.)

The Power Within: How Energy Fuels Our Bodies and Minds

Discover the intricate dance of energy conversion that drives human performance and well-being.
ByRachel B. Levin

An Olympic long jumper stands poised at the edge of the runway, preparing to sprint toward the take-off board. Years of training have prepared her for the moment her feet will push off the ground, sending her airborne and delivering her into the sand with a force up to 12 times her body weight. The athlete’s performance rides on how effectively she will convert the horizontal energy of her sprint into the vertical energy she needs to ascend.

“You have to be able to control these forces strategically,” says Jill McNitt-Gray, a professor of biological sciences and biomedical engineering at the USC Dornsife College of Letters, Arts and Sciences who studies biomechanics in Olympic and Paralympic track and field athletes. “What happens in those last couple of steps is really important.”

But McNitt-Gray explains that the long jumper’s momentum isn’t the only kind of energy that’s crucial during those fateful footfalls. There’s also the caloric energy received through nutrition. The metabolic energy invested in building up the athlete’s bones and muscles to bear the load of the forces. The mental energy cultivated through a positive mindset. And the motivating energy from the roaring cheers of the crowd.

What the Olympic long jumper illustrates in bold strokes is that our bodies are energy made manifest. Though most of us will never tackle such challenging physical feats, we all utilize energy in this multitude of forms to survive and thrive.

Perhaps it’s no coincidence that when we make choices to optimize our energy — from eating healthy foods and staying active to thinking positively and nurturing meaningful connections — our well-being soars.

Fill ’er up

The notion of the body as an energy-generating “machine” dates back to the 17th century, when writers began to describe the body in mechanical terms. Today, we invoke the metaphor of an engine when we say that our “tank” is running empty or that we need to “refuel.”

Food is the body’s primary source of fuel. Our digestive system breaks down the three main macronutrients — proteins, carbohydrates and fats — from food into simpler molecules. In our cells, the energy stored in these molecules is transferred to adenosine triphosphate (ATP), which powers most cellular processes.

ATP “has to be churned out on a minute-by-minute basis,” says Lorraine Turcotte, professor of biological sciences at USC Dornsife. “The job of eating is ultimately to provide nutrients to produce the ATP that we need to just live,” says Turcotte, who studies metabolic function.

But making the right food choices for optimal energy can be tricky. Our evolutionary history has primed us to prefer foods high in fat, as well as sweet-tasting foods.

For our prehistoric ancestors, fats provided a calorie-dense source of energy to sustain them until their next hunt. Their sweet tooth led them to trees or bushes to gather fruit for a more rapid source of energy.

Ours may direct us to the doughnut shop.

“In the modern food industry, foods that we inherently prefer are being prepared in such a way that they’re highly processed, and the sugars are not coming from a natural source,” says USC Dornsife’s Scott Kanoski, associate professor of biological sciences. Kanoski, who studies the neurobiological mechanisms underlying obesity, notes that these foods affect the same brain pathways as addictive drugs, making them difficult for us to resist.

High sugar consumption spikes blood sugar, setting us up for an energy crash. And if our blood sugar climbs too high, too often, diseases like type 2 diabetes can set in. Kanoski’s research has shown that sugar-laden diets lead to damage in the hippocampus, a brain region implicated in memory.

Diets lacking in vitamins and minerals can also imperil our energy. “We need to have all of our vitamins and minerals to maximize utilization of our fuels,” says USC Dornsife’s Grayson Jaggers, associate professor (teaching) of biological sciences.

“The most important dietary advice is also going to be the most boring because it’s what our parents tell us,” says Jaggers, who teaches nutritional biochemistry. “Eat your vegetables and don’t have too many sweets. You can spend billions on nutrition research. And this is always what it comes down to.”

Use it or lose it

In certain affluent corners of the industrialized world, it’s now possible to order groceries with the tap of an app. This stands in stark contrast to the considerable amounts of energy required to obtain food in our prehistoric past.

“The last 2 million years of our physiological evolution occurred in a high-activity lifestyle,” says USC Dornsife’s David Raichlen, professor of biological sciences and anthropology. He notes that vigorous physical activity cues the body to invest energy in metabolic processes that support the body’s ability to be active.

“If we are sedentary, we are essentially telling our bodies that we don’t need to invest energy in thick bones and strong muscles to manage loads, vessel elasticity to support cardiovascular function, etc.,” says Raichlen. Atrophy and disease may follow.

At the cellular level, physical activity helps support the production of ATP in the mitochondria (aka the “powerhouses” of the cell). “The mitochondria of a person who exercises regularly are better adapted to give us ATP at the perfect grade that we need to power our metabolism,” says Turcotte.

Exercise is not only a sound investment of metabolic energy, it can also make us feel more energetic. When you exercise, “you’re providing your body with endorphins, endocannabinoids and all sorts of molecules that improve your mood and your feelings of well-being,” notes Raichlen.

Mind over matter

Food and exercise (and, let’s face it, coffee) fuel our get-up-and-go, but we can also say that the body is itself “electric.” Electrical currents course through our 40 trillion cells (aka the “electrome”),

transmitting signals head to toe. At rest, we generate enough energy to power a 100-watt lightbulb.

When we expend too much mental and physical energy, we find electrical metaphors handy to describe our state: “fried,” “burnt out,” “low batteries.”

Stephanie Eggert, a senior lecturer in USC Dornsife’s Department of Physical Education & Mind Body Health, says that many students show up to her Kundalini yoga classes needing to “recharge.” She explains that from a yogic perspective, much of what drains our energy happens at the level of mindset: perfectionism, overcommitting, negative self-dialogue.

“Kundalini is a system that allows us to allocate our energy toward more efficient pathways,” says Eggert.

In addition to physical yoga poses and breathwork, Eggert’s classes incorporate meditation and mantras intended to redirect the mind away from self-defeating thoughts. Studies have shown that these facets of yoga can indeed disrupt habitual thinking patterns and increase energy. Anecdotally, many of Eggert’s students report that their energy levels transform through the practice — they feel more “radiant.”

USC Dornsife’s Iony Ezawa, assistant professor of psychology, notes that a shift in mindset can also be therapeutic for those suffering from clinical depression.

Fatigue and lack of energy are common symptoms that can become self-perpetuating in depressed individuals. “They’re having that thought, ‘I don’t have the energy to get up today,’” says Ezawa. “And that thought is then impacting their ability to actually get up.”

Cognitive-behavioral therapy (CBT), which challenges negative thought patterns, can be an effective treatment. A therapist might suggest reframing a thought such as “I don’t have the energy to do this” to “Despite my low energy, it’s still possible.”

Often, says Ezawa, “that’s just enough to get the ball rolling. You start to do a little bit, then the energy and the motivation tend to follow.”

The most important dietary advice is also going to be the most boring because it’s what our parents tell us.

Spreading good vibes

The effectiveness of CBT demonstrates that sometimes we need a helping hand to adjust our outlook. Indeed, positive social relationships can buoy and even rekindle our energy.

The USC Dornsife Alumni Mentoring Program offers an excellent example. The program pairs USC Dornsife students with alumni mentors who work in each student’s field of interest. Over a 10-week period, mentors engage their mentees in remote and/or in-person, career-oriented activities such as discussing potential career paths, practicing interview skills and creating vision boards to map the future.

Program Coordinator Laury DeSanctis notes that the program is particularly energizing for students who are unsure how their major will translate into a career. “Being able to talk to their mentor about career paths they may never have considered opens up all kinds of possibilities for them,” she says.

DeSanctis has seen this exchange transform students’ career anxiety into excitement about the future. They become more motivated to excel in their classes and activities and seek out novel opportunities.

“That energy actually goes both ways,” says DeSanctis. Mentors report feeling invigorated by the impact they are making on students, the new directions they begin to envision for their own careers, and the lively buzz of the university environment.

“Honestly, stepping back on campus 20 years later and simply hearing the band can recharge you,” she says.

Speaking of the band…

If you’ve ever gotten amped up while listening to the Trojan Marching Band play “Fight On,” you know that music is a powerful pathway for boosting energy.

“We’re very good at synchronizing our internal rhythm to the rhythm of music,” says USC Dornsife’s Assal Habibi, head of the Brain & Music Lab at USC Dornsife’s Brain and Creativity Institute and associate professor (research) of psychology. “Music that we perceive as exciting and happy increases our heart rate and lifts our mood.”

Music is a balm for social bonds, as well. In her lab, Habibi observes people’s behavior before and after they play drums together. She finds that the more synchronized participants are in their drumming rhythm, the more empathetic and sociable they become toward one another.

From the mentorship dyads to the drum circles, and even to the crowd cheering on the Olympic long jumper, the energy we offer to one another can be infectious — and life-affirming.

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