When it comes to losing weight, working out can be both a blessing and a curse. Burn more calories than you take in and watch those pounds melt off. – But sometimes burn more calories than you take in and watch yourself get even hungrier. We all know the basic math for weight loss is: Calories In < Calories Out = Pounds Lost. But depending on the kind of workout you do, it may also trigger hunger hormones that lead to wanting to eat even more food – or at least eat enough food to replace the calories you just burned.
There is, however, a sweet spot to working out. Research has found that intense exercise (where you get your heart rate up around 75% of your max) affects levels of the hunger hormone ghrelin and peptide YY in a way that actually suppresses your appetite after working out better than less intense workouts (where you get your heart rate up around 50% of your max). This reduction of ghrelin levels lasts for about 30 minutes to an hour following intense exercise.
“An acute bout of high-intensity exercise distributes blood away from the stomach and intestines due to the need for greater circulation of blood to the muscles, which may be a factor involved in appetite suppression. This does not occur with less demanding exercise,” explains David Stensel, Ph.D., a professor of exercise metabolism at Loughborough University in Leicestershire, England. During high intensity exercise, your body needs to circulate more blood in order to prevent overheating. Because eating would cause the blood to flow to the stomach to help aid in digestion, your body dampens your appetite in order to help prevent that. AND to top it off – this effect can last for several hours – maybe even days – after your workout!!
Duration can also be a factor. When people exercise for long periods of time, the suppression of hunger may not be as much. For example. 30-45 minutes of running is better than 60-90 minutes of walking. In fact, a recent study even suggests that interval workouts (where you alternate 30 second bursts of exercise with 1 minute of recovery) may even have a slight edge over sustained vigorous exercise. (Want to know more about interval training? Check Out: Lose Fat & Gain Time – HIIT for the Win or Breaking Through Weight Loss Plateaus or Fitness Myths #6 – Need Cardio For Fat Loss)
However, like all good things, this satiating effect must come to an end – about an hour later, when your body starts to crave the energy it used up. And unfortunately, the desire to refuel may hit women harder than it does men. “Physical activity may raise concentrations of longer-term appetite-stimulating hormones like insulin and leptin in women,” says Barry Braun, Ph.D., associate professor of kinesiology at the University of Massachusetts in Amherst. This is due to the fact that as women we are hard wired to defend our body weight to preserve energy for pregnancy and lactation.
But there is something you can do to combat this!!! Exercising frequently. – Sticking to your exercise plan appears to help restore sensitivity to brain neurons that control satiety. In other words, the more you do it, the more in tune you become with your body, which in the end can help with offsetting all of these hungry feelings you get afterwards. (And if you’re now working out on the reg – a case of the tummy growls here and there isn’t the worst thing to have to deal with when you’ve also got a bangin’ bod to go with it – am I right?!)