Summer is coming and you're thinking about trying on swimsuits and launching a new healthy living kick. Pronto. Especially the diet part. If you are trying to get fit fast, you are likely moving more and eating less — and grappling with the nagging feeling that you can't seem to stop feeling hungry. Here are four reasons you feel that way, and what to do to tame your rumbling tummy.

You forgot the protein

If you're looking to slim down, you may be cutting out too much protein, sabotaging your feelings of fullness. As the Washington Post notes, protein contributes greatly to the feeling of being satisfied. Indulge in some protein at every meal and you will stay full longer. We're not just talking steak, either. Dig into eggs, yogurt, tofu and beans as well as animal proteins.

You didn't get enough sleep

When you are exhausted, you tend to eat more to keep your energy up. In one University of Chicago study, sleep-deprived people ate more than 50 percent more calories than when they had a good night's rest. Those who got enough shuteye lost this urge to eat, researchers found, according to the Daily Mail. So make snooze time a priority to shut off those late afternoon cravings.

Your gut got confused

You know how people say you should go with your gut? Well, the problem is that if the microbes in your gut aren't diverse enough, they may be sending the wrong signals to your brain. As the Washington Post notes, about 20 minutes after a meal, certain bacteria in your gut should send signals that you've had enough to eat by stimulating the release of a hormone linked to feelings of satiety. But if you don't have a very diverse mix of gut bacteria, you may not get that signal. Oops. Experts suggest supping on a diet rich in fiber and probiotics to get back on track.

You're dehydrated

Sometimes you are really thirsty but you mistake that feeling for hunger. The confusion happens in the hypothalamus, the part of the brain that regulates appetite and thirst, according to Health. When dehydration sets in, the wires get crossed in the hypothalamus and you start munching when what you really need is a tall, cool glass of water. Experts recommend that you drink more, starting when you first wake up so you get the hydration you need.