Does Planning to Exercise Make Us Eat More?
During my PhD, through a series of studies, I explored how planning to exercise can influence our eating behaviour. All papers are published in peer-reviewed journals and can be accessed through the relevant links below.
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Happy reading!
Insights from my PhD Research
We often hear that exercise supports better health, and it truly does. Regular physical activity benefits the body and mind in ways no other drugs can. But something less obvious is how planning to exercise, not just the act itself, can subtly influence our eating behaviour.
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During my PhD, I carried out three related studies to explore this question. All involved healthy, active adults who regularly exercised but were not trying to lose weight. What we found was that just anticipating an upcoming workout, even hours before it started, could lead people to change what and how much they ate.
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In the first study, participants were asked to plan their lunch based on a hypothetical morning: either a day of rest, or a morning involving one hour of intense aerobic exercise. Even though no actual exercise took place, participants who were told they'd be exercising planned meals with 24% more calories — suggesting a mental shift in food expectations based on their future plans.
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The second study looked at real eating behaviour before and after a scheduled late-afternoon workout. Participants were free to eat what they liked from a selection of foods at breakfast, lunch, and dinner. Interestingly, they ate around 11% more at lunch when they were expecting to exercise later that day, even though they didn’t report feeling hungrier. Their overall daily intake didn’t increase dramatically, but these subtle changes could matter over time.
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The third study asked: what happens when exercise is planned first thing in the morning, in a fasted state? Here, we found that participants ate more in the evening before the workout, again without a reported change in hunger, as if preparing their body in advance.
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Across all three studies, these patterns suggested that when people know exercise is coming, they may unconsciously “compensate” by eating more before the activity even happens.
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Takeaway
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Exercise is a powerful tool for health; physically, mentally, and emotionally. But it’s useful to understand that our eating habits may shift in anticipation of movement, not just in response to it. Some individuals may see exercise as effort that “rewards” extra food. Others may have internalised messages about fueling for performance.
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While these behaviours don’t undo the benefits of being active, they could influence overall energy balance, something to consider for those pursuing weight management goals.
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It’s important to note that all participants in these studies were young, healthy, and habitually active. That means we can’t assume the same patterns apply to other groups, such as people living with obesity, those managing long-term health conditions, or anyone new to exercise. Future research is needed to explore how these behaviours play out in different contexts.
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In short, movement is medicine, but how we think about eating around exercise can shape how we nourish ourselves, too.