Why High-Intensity Exercise Makes You Crave Cucumbers

There is no doubt that exercise is one of the most powerful ways to “work up an appetite”.

But now, a study by Daniel Crabtree and colleagues from the University of Aberdeen, published in the American Journal of Nutrition, suggests that high-intensity exhaustive exercise may paradoxically increase the appeal of low-caloric foods.

The researchers used functional magnetic resonance imaging (fMRI) to compare neural responses to visual food stimuli after intense exercise and rest in fifteen healthy male volunteers.

Compared to the rest situation, intense exercise significantly suppressed subjective appetite responses as well as ghrelin concentrations while significantly increasing the release of peptide YY (a satiety signal).

In addition, after exercise subjects showed a greater neural appetitive response (activation of the insula and putamen and reduced activity in the orbitofrontal cortex) to images of low-calorie foods (e.g. cucumbers, lettuce, etc.) but lower responses to images of high-caloric foods.

Thus is appears that an acute bout of intense exercise may act as a natural appetite suppressant that tricks the brain into finding low-calorie foods more appealing than fried chicken and pizza.

Unfortunately, the evidence that this approach may actually help you lose weight and keep it off is lacking.

As the authors point out,

“Research has shown that reductions in sensations of appetite after high-intensity exercise are short lived, and appetite responses may rebound over several hours after exercise.”

My guess is that when appetite rebounds, it does so with a vengeance, explaining why exercise alone is such a poor weight loss strategy (despite all its other proven health benefits).

If you have personally experienced intense cravings for cucumber after intense exercise, I’d certainly love to hear your story.

@DrSharma
Edmonton, AB

Crabtree DR, Chambers ES, Hardwick RM, & Blannin AK (2014). The effects of high-intensity exercise on neural responses to images of food. The American journal of clinical nutrition, 99 (2), 258-67 PMID: 24305681