Keeping yourself at a healthy weight is no easy feat. But if you’re not succeeding, don’t be too quick to take all the blame. Carrying around a few extra pounds can be caused by other culprits besides a lack of willpower.

There are specific hormones that play an important role in regulating our weight. Some behaviors and health conditions can affect those hormones, making it harder to keep the scale from going up, let alone shed excess weight. Here’s a look at the link between hormones and weight gain.

When you don’t get a good night’s sleep, you feel tired and cranky the next day. But that lack of sleep doesn’t only mess with your mood - it also sabotages healthy eating habits. Research published in the Annals of Internal Medicine found that people who slept only four hours a night for a mere two nights had a 28 percent rise in ghrelin (a hormone that triggers hunger) and an 18 percent drop in leptin (a hormone that tells your brain that you’re full) compared to those who got a good night’s sleep.

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The result? The sleep-deprived study subjects reported a boost in appetite – and they craved sugary, high-carbohydrate foods, not vegetables. What’s more, if you’re also under constant stress, you’re getting a double-whammy since the stress hormone cortisol increases appetite and the urge to eat high-fat, high-calorie foods.