Post-exercise snack can ruin your workout gains

So you’ve just worked your ass off for over an hour at the gym, using your new smartwatch to track your calories burned, and as you are driving home you have the thought…”I should re-fuel my body ASAP”. But the danger of being so hungry and overly optimistic because of your endorphins may cause you to make a poor decision and ruin all of your hard work.

According to a new study from the University of Nebraska-Lincoln, the time when you decide what you’re going to eat after a workout can dictate what you will eat and potentially undo all of your workout gains. In this study participants had to choose between an apple and brownie, and subjects we found to be more likely to favour the fruit when deciding before vs. after their workouts.

“We found that there was very little research on this very tangible thing that I think everyone can relate to,” said Koehler, assistant professor in the Department of Nutrition and Health Sciences. “If your goal is to lose weight, then I would say our findings support that you’re better off making the choice … not when you’re hungry after your workout, but instead before you go to the gym.”

This finding supports the research on the correlation between timing and food choice. It has been shown that people are much more likely to indulge when making food choices immediately before eating than when thinking ahead, said Gustafson, assistant professor in the Department of Agricultural Economics.

“Our study conformed very closely to the ideas in behavioral economics about this present-biased preference (for unhealthier options),” Gustafson said.

1. Compensatory eating – which suggests that people consume higher calorie food after exercise to compensate for calories burned during a workout.
2. Exercise-induced anorexia – which suggests that exercise actually suppress appetite-related hormones and cause people to eat less.

“There have been a lot of lab studies that have looked at appetite and hunger, most of these studies have found that right after exercise, you seem to be less hungry. I’ve always looked at these studies and wondered: Does it have such a strong impact that you can use this window after you exercise to say, ‘Because I’m not hungry, I’m going to make a really good choice about what I eat’? But knowing myself and many other exercises, there’s also the notion that after you exercise, you want to reward yourself.” Koehler said.

1. Compensatory eating – 6-percent increase in brownie choice between the pre- and post-exercise groups gave some support for the idea of compensatory eating
2. Exercise-induced anorexia – The 12-percent of people that declined a snack in the pre-exercise choice increased to 25 percent at post-exercise.

Did the increase in brownie choice come from the immediacy of the decision-making or from the compensatory eating?

What separates people who exhibit compensatory eating vs. exercise-induced anorexia?

What if there were other healthier choices, would people choose better?

But the evidence is clear, make your decision in advance, and you will be much more likely to feed your body the correct nutrition to maximise your workouts. Now, this notion can also be applied to your daily diet, making the decision of what you will eat the night before and preparing that food will dramatically increase your chances of making better eating choices, which have a compounding effect over time, resulting in a healthier, happier life. So if you are training today, make the decision now to pack your VPA^® protein shake in your gym bag and get the most out of the hard work you are putting into the gym!

The team reported its findings in the journal Nutrients. Koehler and Gustafson authored the study with Nebraska’s Ajai Ammachathram, assistant professor in the Department of Nutrition and Health Sciences; Nigina Rakhmatullaeva, graduate student in agricultural economics; Safiya Beckford, graduate student in nutrition and exercise physiology; and Alexander Cristobal, senior in nutritional science and dietetics.

The researchers received support from the University of Nebraska’s Food for Health Collaboration Initiative.