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Can Plants Fuel Champions?

With vegans competing in high-profile competitions across the world, researchers and dietitians are asking if a plant-based diet limits鈥攐r enhances鈥攁thletic performance.
ChemMatters
Vegan protein sources (plants, nuts) next to a dumbbell
Credit: Shutterstock

by聽Grant Curin


Heidi Lynch grew up on a聽meat-based diet. In her聽Chicago, Illinois-area home, fish聽and grilled chicken were weekly staples. On special occasions, they had pork chops. 鈥淢y family was active and health conscious, but I never knew anyone vegetarian,鈥� she says.

She was also an athlete, swimming for Ver-non Hills High School her sophomore through聽senior years. 鈥淚 wasn鈥檛 very fast, but I loved it,鈥� she says. 鈥淭hat鈥檚 when I became interested in how food fueled athletic performance.鈥澛�

Though she had planned to become a physical therapist, Lynch decided to study nutrition. She earned a bachelor鈥檚 degree in applied health science, a master鈥檚 degree in nutrition, and a doctorate in physical activity, nutrition, and wellness.

For an athlete, eating well can help speed recovery. It can prevent injuries. The right diet can even mean the difference between victory and defeat. That鈥檚 why so many athletes who compete at the highest levels and their coaches are obsessed with optimizing what they eat.

While most athletes鈥攍ike most people鈥攅at an omnivorous diet that includes plants, animals, and fungi, a sizable number of elite athletes have chosen to avoid eating animal-based food altogether.聽

And it works for them. Vegan and vegetarian athletes compete in the Olympics, the NBA and WNBA, and the highest levels of surfing, snowboarding, tennis, and soccer. They win everything from marathons to powerlifting competitions.

Of course, professional athletes aren鈥檛 a random sample of the population. These athletes are different in several key ways. For one thing, they鈥檙e likely to have exceptional physical traits, such as the ability to use oxygen more effi ciently or a tendency to grow a certain type of muscle more easily. They also have the resources to focus on eating a fi ne-tuned diet tailored just for them, perhaps with the help of a team nutritionist.

So, a plant-based diet clearly can work for some people鈥攂ut what about the rest of us?

What Does It Mean to Eat?

When you sit down for a meal, the body starts working to break down food before the first bite even enters your mouth. The saliva you produce contains enzymes that convert starches into sugars and lubricates your food as it passes through the digestive tract.聽

鈥淭he whole purpose of eating is to break food down into its constituent components for cells to use,鈥� says Lynch, who is a a registered dietitian.聽

The journey isn鈥檛 easy. It takes food聽hours to travel through the 10-meter digestive tract. During that time, the body will crush food, saturate it in acid, and use enzymes and emulsifiers to extract basic nutrients. Then it will use a range of chemical reactions and highly specialized molecules to collect these vital materials and transport them through the body.

The reason diet is vital for peak athletic performance is because what a person eats determines what materials are available to the 30 trillion cells in their body. That鈥檚 where the biggest differences between an omnivorous diet and a plant-based diet lie.

鈥淐learly there are differences in nutrient intake between the average omnivorous diet versus the average plant-based diet,鈥� Lynch says. 鈥淭hat鈥檚 why it鈥檚 important for researchers to study the impact of different diets on athletic performance and overall health.鈥�

Without the right fuel for their cells, an athlete can鈥檛 compete to the best of their ability or recover properly.

Energy to Run, Jump, and Survive

The energy an athlete uses to sprint, lift, or swing comes, ultimately, from nuclear reactions that occur near the center of the sun. Plants use photosynthesis to convert that electromagnetic energy from sunlight into glucose, which they use as an energy source and building block to grow leaves, stems, roots, and flowers.

When a human eats, the body digests the food and converts the carbohydrates, proteins, and fats into energy and materials that are useful for us. The biggest difference between animal-based food versus plant-based food is the distribution and composition of proteins and saturated and unsaturated fats. While it鈥檚 possible for the body to use protein for energy, that only happens under certain circumstances, like deep into an ultramarathon.聽

鈥淯sually, the energy to do anything鈥攆rom practicing sports to just walking to class鈥攃omes from carbohydrates and fat,鈥� Lynch says. 鈥淭he body uses those carbohydrates and fats to make ATP.鈥� Adenosine triphosphate (ATP) provides energy to the cell when one of the three phosphate groups breaks away.

The energy in food is stored in the bonds that connect the atoms within carbohydrate or fat molecules. The body uses biochemical pathways with many, many steps to transform this chemical energy into a usable form.聽

Carbohydrates get broken down into the simple sugar glucose. From there, cells convert glucose into ATP through biochemical processes such as glycolysis and oxidative phosphorylation. Glycolysis is a series of reactions that extract energy in the form of ATP from glucose by splitting it into two three-carbon molecules called pyruvate. In the oxidative phosphorylation process, electrons are passed along a series of proteins and organic molecules found in the cell鈥檚 mitochondria by a series of redox reactions that release energy. Fats are broken down through a process called beta-oxidation into molecules, such as acetyl-CoA, which then enter the citric acid cycle to produce ATP.

鈥淭he average omnivorous diet tends to be a little bit higher in total energy, as well as saturated fat, total fat, and cholesterol,鈥� Lynch says. 鈥淧lant-based diets tend to be higher in fiber and unsaturated fats and lower in omega-3 fatty acids, which humans need for specific functions.鈥� An unsaturated fat has double bonds in its long carbon chains, while a saturated fat has only single bonds in its carbon chains.聽

Researchers are still working to figure out聽how different forms of fat impact health, but most evidence suggests that eating a lot of saturated fat is associated with chronic health conditions.聽

But What About Protein?

After an intense practice session, when your muscles ache and you鈥檙e still catching your breath, your body has already jumped into self-repair mode. The training will pay off when muscles grow back stronger.聽

Of course, your body needs the right building materials to make this happen. That鈥檚 why protein is so vital. 鈥淲e use proteins to make and repair all sorts of components in the body,鈥� Lynch says. 鈥淓veryone thinks of skeletal muscle, but there鈥檚 also hormones, enzymes, transport proteins, and connective tissue, to name just a few.鈥澛�

Because athletic performance depends on overall health, these other tissues and substances are a vital piece of the puzzle. 鈥淧roteins get broken down into their individual amino acids and then reassembled to form various proteins in the body,鈥� Lynch says.聽

Amino acids are the building blocks of proteins. Our bodies need 20 amino acids to survive and thrive. The human body can produce 11 of those on its own, but the other 9 must come from food. Nutritionists call these amino acids essential amino acids.聽

Each amino acid has a central carbon bonded to an amino group (鈥揘H鈧�), a carboxyl group (鈥揅OOH), a hydrogen atom, and a unique side chain called an R-group. The R-group determines the amino acid鈥檚 properties. Like Legos snapping together, amino acids are linked through peptide bonds to form proteins. These proteins fold into specific shapes to do certain jobs within and between cells.

鈥淲e get all amino acids in the proportions that our bodies need when we鈥檙e eating animal-based sources of food,鈥� Lynch says. That鈥檚 because humans, as mammals, are made of the same basic materials as chickens, cows, pigs, and fish. The picture with plants is a little more complicated.

鈥淪ome plant sources, like soy or the grain quinoa, do have all nine of the essential amino acids in proportions similar to animal protein, but most plants are low in at least one of them,鈥� Lynch says.聽

Does that mean plant-based athletes are destined for a lifetime of quinoa bowls and tofu burgers? Not anymore.聽

鈥淧eople used to get pretty stressed about trying to pair complementary proteins together,鈥澛燣ynch says. The goal was to combine plant-based foods that were low in different essential amino acids. The idea was to make meals that offered a protein profile like meat.

鈥淲hat the research has shown is that we don鈥檛 need to do that, as long as people are eating a variety of foods over the course of the day,鈥� Lynch says. 鈥淰ariety is key.鈥�

The importance of eating a wide range of foods extends beyond the nine essential amino acids. The body also needs small amounts of specific vitamins and minerals to maintain a baseline level of health. These micronutrients鈥攕uch as iron, iodine, folate, zinc, and vitamins A and D鈥攁re only needed in small quantities, on the scale of a milligram or less, but they are essential for peak performance.

It's a Little More Complicated

When it comes to getting important macronutrients and micronutrients from food, the sheer amount of a particular substance doesn鈥檛 tell the whole story. There are other factors to consider.聽

For instance, some plants will bind certain compounds to amino acids. Those larger molecules are harder for the body to digest, so a vegetarian may have to eat slightly more of a particular amino acid to get the same benefit as eating animal-based protein.聽

Similarly, vegetarians need nearly twice as much iron as nonvegetarians鈥攂ut for a different reason.

In plants, iron exists by itself as an ion, usually Fe3+. Fe3+ is not bioavailable鈥攁ble to be used by the body鈥攕o, the first thing the human body must do is add an electron鈥攔educe鈥攖he iron to Fe2+. That limits the amount of iron our bodies can absorb.聽

In meat, the iron ions are coordinated to a special organic molecule, heme, which is a聽porphyrin that is found in proteins, such as hemoglobin and has an Fe2+ ion in the center. Heme iron is easier to absorb, so omnivores need less of it than people who are relying on plants for their micronutrients.

For vegetarians, 鈥渋t鈥檚 important to consume sufficient amounts of plant-based iron,鈥� Lynch says. She also suggested 鈥渂eing strategic鈥� by pairing plant-based sources of iron with certain acids, such as vitamin C. Those can help reduce the Fe3+ by donating electrons, assisting the body鈥檚 effort to convert them into usable Fe2+ 颈辞苍蝉.听听

So, Can Plants Fuel Champions?

The history of sports is packed with stories of athletes fueling their victories with animal products. A hundred years ago, it was boxers down-ing raw eggs mixed with heavy cream between聽rounds. More recently, Michael Phelps鈥擴.S. Olympic Swimming Gold Medalist鈥攚as starting his 10,000-calorie days with three fried-egg sandwiches and a five-egg omelet.聽聽

What does the evidence say? According to Lynch, eating a plant-based diet has surprisingly little impact on athletic performance.聽

鈥淐onsidering all the data so far, we don鈥檛 see either an advantage or disadvantage,鈥� Lynch says. 鈥淲hen we look at absolute outcomes鈥攚hether strength, power, or speed鈥攚e don鈥檛 see compelling differences between groups of athletes who eat animal products and those who follow a plant-based diet,鈥� she says.聽

Researching the impact of nutrition is too difficult to make ironclad claims about how a particular diet affects any particular athlete, but the best available data suggests that a good plant-based diet is no better or worse than a good omnivorous diet.

As Lynch says, 鈥渋t鈥檚 less about the specific聽foods on your plate and more about making sure those foods provide the nutrients your body needs.鈥澛�


REFERENCES

Haider, L. M.; Schwingshackl, L.; Hoffmann, G.;聽Ekmekcioglu, C. The Effect of Vegetarian Diets on Iron Status in Adults: A Systematic Review and Meta-Analysis. Crit. Rev. Food Sci. Nutr. 2018, 58 (8), 1359鈥�1374. .

Hatton, I. A.; Galbraith, E. D.; Merleau, N. S. C.; Miettinen,聽T. P.; Smith, B. M.; Shander, J. A. The Human Cell Count and Size Distribution. Proc. Natl. Acad. Sci. 2023, 120 (39), e2303077120. .

Vasenina, E.; Sterner, D. A.; Mangum, L. C.; Stout, J. R.;聽Fukuda, D. H. Effects of Vegan and Omnivore Diet on Post-Downhill Running Economy and Muscle Function. J. Am. Nutr. Assoc. 0 (0), 1鈥�10. .


Grant Currin is a freelance science writer and strategic communications professional based in Brooklyn, New York.


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