The Science Behind HIIT Post-Workout Hunger

High-intensity interval training (HIIT) is one of the most popular forms of exercise thanks to benefits like better cardiovascular health and a higher calorie burn with a smaller time commitment. These intervals of high effort and rest can also be adapted to pretty much any activity — even walking — making HIIT a versatile training style that works for people of all fitness levels. There’s just one catch: Many people who use HIIT workouts feel hungrier than usual afterward.

For some, that might not be an issue, but for anyone pursuing weight loss or maintenance, a bigger appetite may mean it’s harder to stick with daily food goals. “Many of my clients are in a caloric deficit because their goal is to lose weight, and they are already generally hungry,” explains Caroline Freeman, a personal trainer at Crunch Gym. “HIIT can exacerbate this feeling.”

Feeling hungry after a workout is totally normal, according to Marisa Michael, a registered dietitian and sports nutritionist. “Hunger is just your body’s way of saying you need to fuel it.”

But there’s no agreed-upon reason as for why HIIT seems to make people feel hungrier than other types of workouts. In fact, it may happen to different people for different reasons, experts say.

One potential factor is excess post-exercise oxygen consumption (EPOC). In the hours after a HIIT workout, your body needs more oxygen than usual to recover. This phenomenon is associated with increased calorie burn, which is one of the reasons HIIT is believed to be so effective — you’re going to continue burning calories even after your workout has ended. But during this time, your body is working to return itself to its normal metabolic state, which could lead to increased hunger, says Freeman.

Another theory is HIIT may affect hunger and fullness hormones, especially in people who are already active. “In one study on athletes, leptin levels (a hormone that makes you feel full) were decreased after HIIT workouts,” notes Michael. “Leptin is also lower in those with less body fat. So if you are a really lean person doing HIIT workouts, you’ll likely feel hungry because you have less leptin.” In other words, your body knows it needs more food and is sending you signals to give you a heads up that it’s time to eat. “It’s a way for the body to preserve itself and get the calories it needs,” she adds.

It could also be partly in your head. “Often times, people relate the amount of sweating that occurs in a workout to the amount of calories burned,” says Freeman. In turn, they perceive that they need to refuel to a higher degree after a super sweaty HIIT workout than something more moderate. Research shows people tend to overestimate their effort and calorie burn in workouts, though, so it may be the case that it’s not your body telling you it needs more food post-workout, but your mind.

None of this means HIIT isn’t worth doing if you’re watching your weight. Instead, you just need the right strategies to get the most benefit from your workout while avoiding overeating later. Here are three smart ways to deal with HIIT hunger, according to fitness experts:

1. MAKE SURE YOU’RE HYDRATED

“Dehydration and hunger are often perceived as one in the same,” says Freeman. So if you’re feeling hungrier than usual, make sure you’ve had enough water during and post-workout.

2. REFUEL PROPERLY

”To manage hunger after a workout, be sure to eat something as soon as possible,” recommends Michael. “This could be a balanced meal or snack with complex carbs, protein and a healthy fat.” Aim for about 10–20 grams of high-quality protein — something like a turkey sandwich or a protein shake.

3. REMEMBER THAT HUNGER CAN BE TRAINED

“Feeling hungry is a mental muscle that must be trained around, just like the muscles you train physically,” says Freeman. Of course, it’s important to eat enough food, and you shouldn’t ignore ravenous hunger. But, if you’ve had a hearty post-workout meal and you’re still feeling hungry, try holding off to see if the hunger subsides. Consider whether you’re truly hungry or if it’s more that you want to keep eating.