Your lunch break rolls around, you eat the healthy meal you packed this morning, and you’re feeling pretty proud of yourself. Then the after-lunch slump hits, and the vending machine in the break room begins calling your name. You fight the urge as long as possible, until your will power finally snaps. It’s 3:30 pm and you’ve just devoured a bag of chips, a package of snack cakes, and a can of soda.

Now you’re feeling a bit embarrassed, and disappointed that you’ve fallen off the healthy-eating bandwagon once again. Why does this keep happening? Why do you lose your cool around food, and overdo it?

This scenario is more common than you might think. First of all, there’s no need to feel shame over it. We’re all human and we all do this from time to time. But in order to correct the behavior, it might help to learn some of the common reasons that ravenous hunger tends to strike.

You’re not eating enough protein. If you’re filling up on fruits and veggies, you’re doing a great job at nourishing your body. But you won’t stay full for long, without adding protein and fiber to your meals. Add some sliced turkey breast, grilled chicken, or a packet of tuna to your salad. Vegans can opt for chickpeas, lentils, or another favorite protein source.

You’re not eating enough fruits and veggies. Conversely, some people aren’t eating enough produce. Its high water content helps prevent overindulgence on more calorie-dense foods. Plus, fruits and veggies keep you hydrated, which brings us to our next point…

You’re thirsty. For some reason, our brains often confuse thirst and hunger signals. So when you find yourself reaching for a snack an hour after lunch, ask yourself if you’re really just thirsty.

Your portions are out of whack. After reading the first two points of this article, you might be wondering what you should be eating – produce or protein? The answer is, both. A good rule of thumb is to fill your plate about half full with fruits and vegetables, and about half with protein.

You’ve been fasting. Fasting can be useful, or is sometimes done for religious purposes. But if you’re simply too busy to eat all day, that’s not a mindful fast. Later you’re going to feel ravenous, and probably overeat fatty or sugary foods.

You’re anxious. If you tend to overeat at parties, you might have a touch of social anxiety. Do you feel like hanging around the snack table gives you something to do, keeping your hands and mouth occupied? There’s no easy fix for social anxiety, but try locating a non-food activity that is going on elsewhere at the event. At the very least, grab a glass of water and sip on it when you need to feel less awkward.

Do any of these reasons sound familiar? If so, now you can take the steps to anticipate your food triggers, and avoid them. We all indulge from time to time, and there’s no reason to feel bad about it. But since a healthy diet (and moderation in portion sizes) is a major key to good health, more mindful eating from now on can prevent many common diet-related problems.