Intense Exercise While Dieting May Reduce Cravings for High-Fat Food

In a new study offering hope for dieters, rats on a 30-day diet that exercised strongly resisted signals from favored high-fat meal pellets.

The experiment was designed to test resistance to the phenomenon known as “craving incubation,” which is the longer a desired substance is denied, the harder it is to ignore the cues. The findings suggest that exercise modulated how hard the rats were willing to work for cues associated with the granules, reflecting how much they craved them.

While more research is needed, the study may indicate that exercise can reinforce moderation when it comes to certain foods, said Travis Brown, a physiology and neuroscience researcher at Washington State University.

“A really important part of sticking to a diet is having some brain power — the ability to say ‘no, I may be craving that, but I’m going to abstain,'” said Brown, corresponding author of the study published in the journal Journal. Obesity. “Exercise may not only be beneficial physically for weight loss, but also mentally for curbing cravings for unhealthy foods.”

In the experiment, Brown and colleagues from WSU and the University of Wyoming trained 28 rats with a lever that, when pressed, turned on a light and emitted a tone before dispensing a high-fat pill. After the training period, they tested to see how many times the rats would press the lever just to get the light and tone signal.

The researchers then divided the rats into two groups: one underwent a high-intensity treadmill running regimen; the other had no additional exercise outside of their regular activity. Both groups of rats were denied access to the high-fat pellets for 30 days. At the end of that period, the researchers gave the rats access to the levers that once dispensed the pellets again, but this time when the levers were pressed, they only gave the light and tone signal. The non-exercising animals pressed levers significantly more than the exercising rats, indicating that exercise decreased craving for the pellets.

In future studies, the research team plans to investigate the effect of different levels of exercise on this type of craving, as well as how exactly exercise works in the brain to curb cravings for unhealthy foods.

While this study is novel, Brown said it builds on the work of Jeff Grimm at Western Washington University, who led the team that first defined the term “desire incubation” and has studied other ways to subvert it. Brown also credited research by Marilyn Carroll-Santi at the University of Minnesota showing that exercise can mitigate cocaine cravings.

It is still an open research question whether food can be addictive in the same way as drugs. Not all foods appear to have an addictive effect; as Brown noted, “no one overeats broccoli.” However, people seem to respond to cues, such as fast-food ads, encouraging them to eat foods that are high in fat or sugar, and those cues can be harder to resist the longer they stay on the diet.

The ability to ignore these cues may be another way exercise improves health, Brown said.

“Exercise is beneficial from several perspectives: it helps with heart disease, obesity and diabetes; it might also help with the ability to avoid some of these maladaptive foods,” he said. “We’re always looking for this magic pill of some sort, and exercise is right in front of us with all these benefits.”

Reference: “Acute High-Intensity Interval Exercise Attenuates High-Fat Craving Incubation” by Georgia E. Kirkpatrick, Paige M. Dingess, Jake A. Aadland, and Travis E. Brown, Apr 6, 2022, Obesity.
DOI: 10.1002/oby.23418