Hunger: a primal instinct
Hunger is your instinctive drive to find food. If you go a long time between meals, or eat less than normal, ghrelin (the "hunger" hormone) is elevated, sending signals to your brain to eat.
The relationship between exercise and hunger
Just as exercise and weight loss is a complex relationship, so too is physical activity and appetite. Burning calories through exercise makes your body crave food in order to replenish your energy stores. However, a recent scientific review suggests that certain workouts deplete your energy stores more than others - having greater potential to stimulate growling in your belly.
How to tame the hunger beast
A heightened hunger doesn't mean you should forgo your fitness routine. Getting your 20 to 30 minutes a day is essential to your health for a myriad of reasons. Instead, try these tips:
Keep hydrated: Your body commonly mistakes thirst for hunger. So, if you're not careful, a big sweat out could leave you thinking you need to eat. Make sure you hydrate before, during and after a workout to avoid misdiagnosed hunger.
Play around with intensity: It makes sense that the more calories you burn, the hungrier you'd feel, right? In fact, higher-intensity workouts (like a spin class) temporarily suppress appetite (at least temporarily); whereas lower-intensity exercise (like pilates) trigger heightened production of ghrelin.
Why? Intense effort triggers higher volumes of blood and energy to be diverted to the muscles, heart and lungs. In other words, the more blood you're pulling away from the gut, the less hungry you're going to feel.
But this doesn't mean you should wait for hunger to kick in before refuelling. Always consume a post-workout snack that contains a balance of carbohydrates and protein (e.g. chicken wrap or fruit smoothie) around 30 minutes - 1-hour post workout.
Be mindful of duration: The length of your workout also can affect how hungry you get, as the body can perceive a long workout as a famine making you really hungry (even if it's not right away).
In some cases, weight gain can occur while training for ultra-endurance events, such as marathons due to a higher propensity to overcompensate with calories, despite burning a large amount. To prevent overeating, plan your post-workout meal or snack before working up a sweat.
Be wary of weights and water: Weightlifting and water sports are real hunger-driving culprits. This is because pumping iron causes micro tears in the muscle. As they repair, your muscles grow bigger and stronger. So, the more muscle you have, the hungrier you get.
As for water sports, like swimming and water polo they are extra hunger-inducing because the temperature of the water cools down your body. Being immersed in water also causes you to use every muscle in your body, so you tend to deplete energy stores quicker.
The bottom line
A little hunger should never put you off adding activity to your day. It's a vital component to your wellbeing, brain function, heart health, energy and disease-fighting immunity.
