We know that physical activity is a key component to successful weight loss and maintenance, especially when paired with healthy food (energy) intake.
However, some research suggests that differences in weight loss might be explained (at least partially) by an increase in energy intake to compensate for the energy expenditure of physical activity.2
So, does exercise cause us to eat more?
To see if this is true or not, recent interest has focused on the effect of a short-term bout of exercise on hunger and energy intake. In other words, if you were to exercise in the morning, would you be hungrier and eat more at lunch – compared to if you did not exercise?
Short-Term Exercise and Hunger
Despite what many might believe, there is little to no current evidence that short-term (acute) exercise increases hunger or energy intake in normal weight, overweight or obese adults.1,4,6,7 In actuality, short-term exercise might actually have a satiating (hunger reducing) effect in the short-term.3,7
Perhaps exercise intensity could be the culprit? A recent study with 12 overweight/obese volunteers put this question to the test.5 Participants exercised across three different conditions that expended the same amount of energy (250 Calories), plus a control condition:
1. Short duration high-intensity intermittent cycling
2. Long duration high-intensity intermittent cycling
3. Moderate intensity continuous cycling
4. No exercise control (just sat there)
Participants completed each of the 4 conditions 1-hour after breakfast, and everything from appetite to hormones were measured for 3 hours after the exercise bout.
What Did They Find?
Their findings support that exercise, even at varying intensities, did not increase appetite. Also, those in the exercise conditions did not eat more food or more unhealthfully during their lunch meal following their post-breakfast exercise session.
The authors conclude, "Our findings suggest that, in overweight/obese individuals, isocaloric bouts [same amount of Calories expended] of moderate- or high-intensity exercise lead to a similar appetite response. This strengthens previous findings in normal-weight individuals that acute exercise, even at high intensity, does not induce any known physiological adaptation that would lead to increased [energy intake]."
Does Sitting Make Us Hungry?
Interestingly, this study provides evidence that just sitting there, such as at work, might actually increase appetite! While the exercise conditions reduced hunger during and after exercise, the control condition, where participants just sitting there 1-hour after breakfast, had an increase in hunger.
250 Calories vs. 600 Calories?
So, exercising enough to expend 250 Calories, which is quite normal and doable for most people, does not appear to be enough to increase one's appetite. For perspective, it would take a 150 lbs person going on a brisk walk (2.5 mph) about 75 minutes to expend 250 Calories, and a 200 lbs person about 55 minutes.
But, what about 600 Calories? Maybe, if we expended nearly 3 times the amount of energy, we would eat more?
Well, researchers found that 60-minutes of exercise expending about 600 Calories did not increase appetite or food consumption – rather was able to reduce appetite and the amount of food eaten at a lunch in obese, adult men.8 They ate breakfast at 8:50 am, exercised (or sat quietly) at 10:00 am for 1-hour, and then ate lunch at 12:00 pm.
During lunch, the exercise condition ate an average of 614 Calories, compared to 944 Calories when they just sat quietly during that hour – a difference of 330 Calories.
The current research supports that short bouts of exercise do NOT increase our appetite, rather it might actually help reduce it in the short-term. Exercising before lunch for 60 minutes, compared to sitting for 60 minutes, was shown to reduce how much food was eaten at lunch by an average of 330 Calories.
Thus, physical activity might be an advocate for energy intake control, rather than an adversary. Sitting might be our more potent adversary.
More research is needed to determine long-term effects of exercise on metabolism, hunger- and energy-related hormones, and subsequent weight control. Stay tuned.
Food Quality and Hunger
One final, important note regarding food choice that I think is very relevant here. The amount of Calories we eat (quantity), is highly impacted by the 'quality' of food we choose.
Even if exercise did make you hungry, consider the following two meal choices:
- Grilled eggplant (1/2 whole), broccoli (2 cups), a sweet potato (1 large), a little olive oil (1/2 Tbsp), and a 16 oz water.
- Quarter-Pounder with cheese, 32 oz Coke, and an order of large fries.
We know the nutritional differences, but what about Calories?
- 319 Calories
- 1338 Calories
That is a difference of over 1,000 Calories, simply by focusing on the 'quality' of the food choices. So, you could eat either of these meals for your lunch following a morning workout.
Which would you choose?
- Donnelly, J. E., Herrmann, S. D., Lambourne, K., Szabo, A. N., Honas, J. J., & Washburn, R. A. (2014). Does increased exercise or physical activity alter ad-libitum daily energy intake or macronutrient composition in healthy adults? A systematic review. PloS one, 9(1), e83498.
- King, N. A., Hopkins, M., Caudwell, P., Stubbs, R. J., Blundell, J. E. (2008). Individual variability following 12 weeks of supervised exercise: Identification and characterization of compensation for exercise-induced weight loss. International Journal of Obesity (London), 32:177–84.
- Martins, C., Morgan, L. M., Bloom, S. R., & Robertson, M. D. (2007). Effects of exercise on gut peptides, energy intake and appetite. Journal of Endocrinology, 193(2), 251-258.
- Martins, C., Morgan, L., & Truby, H. (2008). A review of the effects of exercise on appetite regulation: an obesity perspective. International Journal of Obesity, 32(9), 1337-1347.
- Martins, C., Stensvold, D., Finlayson, G., Holst, J., Wisloff, U., Kulseng, B., ... & King, N. A. (2015). Effect of moderate-and high-intensity acute exercise on appetite in obese individuals. Medicine and Science in Sports and Exercise, 47(1), 40-48.
- Schubert, M. M., Desbrow, B., Sabapathy, S., & Leveritt, M. (2013). Acute exercise and subsequent energy intake. A meta-analysis. Appetite, 63, 92-104.
- Schubert, M. M., Sabapathy, S., Leveritt, M., & Desbrow, B. (2014). Acute exercise and hormones related to appetite regulation: a meta-analysis. Sports Medicine, 44(3), 387-403.
- Ueda, S. Y., Yoshikawa, T., Katsura, Y., Usui, T., Nakao, H., & Fujimoto, S. (2009). Changes in gut hormone levels and negative energy balance during aerobic exercise in obese young males. Journal of Endocrinology, 201(1), 151-159.