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Christine Skopec/ MEDILL 

Amanda Hamilton, 35, struggles to maintain her appetite while marathon training 


Athletes struggle with a loss of appetite

by Christine Skopec
May 21, 2014


RENEE1

Christine Skopec/ MEDILL  

Renee Young, 37, can't tolerate anything more than liquids after intense workouts 

Easy-to-digest foods for athletes

Soup

Crackers

Pretzels

Jell-O

Pudding

Chocolate Milk

Sports drinks


Despite the attention given to obesity, some active Chicagoans find themselves struggling to maintain their appetite following a run or session at the gym.

Hunger suppression can be a response to adrenaline and hormones that kick in during intense exercise. But maintaining nutrition is a must for athletes and experts offer tips on foods that can be easily tolerated. 

Amanda Hamilton, a traffic controller from Elgin, finds it difficult to eat enough food because of suppressed hunger after running.

“I tend to lose weight during the longer training,” said Hamilton, who has run 13 races of marathon-length or farther.

Many people find they are starving after exercise since it burns calories and increases the total amount of energy they need to consume. But a couple of factors can actually contribute to appetite suppression.

Exercising increases physical stress and raises levels of adrenaline. This fight or flight mode forces the body to focus on providing ample blood-flow to the areas that are being stressed like the legs, heart and lungs.

“Our bodies are always suppressing blood flow to other areas,” said Craig Horswill, Ph.D. and professor of kinesiology and nutrition at the University of Illinois at Chicago. Physical activity demands blood so Horswill said “you really don’t need it to be going to your gut.” He added that exercise “directs our physiology away from eating.”

Exactly how long suppressed blood-flow impacts hunger is unclear since it varies from person to person. Renee Young, a triathlete who sells commercial insurance in Chicago says her appetite level varies with her workout schedule. Sometimes she will not be hungry for the entire day.

“I make myself eat something in the evening,” Young said. “I choke something down – it’s hard.”

For endurance athletes like Young and Hamilton, the effects can be even more pronounced than for those who exercise at a more moderate level because the intensity and length of training for something like a marathon or triathlon leads to tissue breakdown.

“If you’re having muscle breakdown, that can cause it,” said Dr. Lisa Neff, assistant professor of endocrinology at Northwestern University. She explained appetite loss can occur from tissue damage that is usually associated with illness, like certain cancers or liver disease. Intense exercise can be similarly stressful on the body.

There may, however, be something else at play. More recent research suggests exercise may influence the body’s production of certain hunger hormones.

Matt Schubert, a Ph.D. candidate in nutrition and exercise physiology at Griffith University in Gold Coast, Australia, conducted a meta-analysis of studies analyzing the impact of exercise on hunger hormones. The meta-analysis, an evaluation and comparison of a collection of similar studies, found exercise affected the hormone that makes people hungry, such as ghrelin, and hormones that contribute to fullness, peptide YY, glucagon-like peptide 1, and pancreatic polypeptide.

“Our second paper found that exercise reduced concentrations of active ghrelin,” said Schubert. Simultaneously, fullness hormones “all increased after exercise,” he said. This suggests that appetite would decrease by reducing levels of the hormone that makes people hungry and increasing the hormones that make people feel full.

While this research offers evidence indicating a person might be less hungry after exercise, it does not always translate to an overall decrease in calorie consumption.

As part of the analysis, Schubert said “changes in ghrelin after exercise do not seem to relate to energy intake when a test meal is offered.”

This means that many people eat their regular meals regardless of whether or not they are actually hungry. They eat based on social norms rather than what their appetite dictates.

For those who struggle to eat enough calories after working out, there are strategies that can help, says Laurie Schubert, no relation, a sports dietitian in Naperville.

“If they can start [hydrating] right away, that’s going to be better than nothing,” she said. She suggested “simple sugars, in this situation, are going to be best,” rather than foods high in fiber or protein.

Both Young and Hamilton push the fluids after hard workouts since it’s easiest on their stomachs.

“I think chocolate milk is probably good,” Hamilton said.

How do athletes find out what types of foods they can tolerate after strenuous physical activity? It comes down to trial and error.

As athletes work to balance their nutritional needs with their appetite they should “develop a list of things they can get down,” Laura Schubert said.