Monday through Friday, you’re working hard on those healthy habits, spinning smoothies and salads, and stepping it up with your workouts. But if you’re pounding cheeseburgers and sneaking a second scoop of ice cream by the end of the week, you could be sabotaging all of your hard work. Especially during the summer, it’s so easy to let weekends fill up with beers and barbecues. Yes, you totally deserve to treat yourself. But before you completely cut loose, it’s important to think about what happens to your weight goals when one treat turns into an entire cheat weekend.

It’s completely normal for your weight to go up and down throughout the week. A study from the Cornell Food & Brand Lab found that on average, people weigh the most on Sunday night, and the least on Friday morning. So it is possible to lose weight during the week, slide back a little on the weekend, and still make progress overall. And plenty of people love their cheat days and swear they couldn’t survive without them.

The problem is when cheating gets out of control. “There’s good evidence that looking forward to a treat can help you stay on track with a healthy diet,” says Ginger Hultin, MS, RDN, CSO, and spokesperson for the Academy of Nutrition and Dietetics. “But too often, cheating can be a sign that your diet is too restrictive, and I worry about the negative connotations. If you’re binge eating or developing a bad relationship with food, that’s a problem.” Here are a few red flags to watch out for.

They can destroy your gut bacteria. Alcohol, sugar, and processed foods are a punch to the gut, and a weekend is enough to do damage. One animal study revealed that eating junk food for even a couple of days can be just as harmful as eating junk all of the time.

They can contribute to inflammation. Likewise, bad food choices can lead to inflammation throughout your body, and it only takes a day or two to flare up. “Inflammation happens quickly,” Hultin confirms. “And unhealthy foods put a heavy load on your hormones and liver.”  

They can give you a sugar crash—and cravings. Sugar gives you a rush and drop, and it’s incredibly addictive. Eat one small sweet, and you might be tempted by another. Go crazy for a few days, and you’re setting yourself up for cravings all week.  

They can make you tired. Bloated, achy, and crave-y—is it any wonder you come out of the weekend feeling sluggish? “Binges tank your energy,” explains Hultin. “Especially when alcohol is involved, which can also hurt your sleep, and prevent you from getting real rest.”

They can compromise your immune system. Alcohol can also suppress your ability to fight off illness-causing viruses and bacteria. Even one big night of drinking can lower your immune system for 24 hours afterward.  

They can feed guilt and negative feelings. If the only thing that gets you through the week is dreaming about Friday night pizza, and then all you can think about on Monday is how gross you feel—that’s not healthy. “If you’re overly fixated or suffering from guilt, those are signs of a bad relationship with food,” says Hultin. “Maybe cheat days aren’t working for you.”  

If your weekend cheat days feel out of control, or if they’re hurting your body or your mindset—kick those negative thoughts to the curb. Take a more positive approach, by calling it a “treat,” instead of a “cheat.” You might decide that your treat is just one item (an ice cream cone), just one plate of food (barbecue), or just one meal that falls within a certain time frame (dinner at your favorite restaurant). Hultin isn’t worried about the specific parameters, as long as they work for you, and you’re still tracking to your health goals. “My credo is that it’s always okay to eat what your body wants to eat,” she reassures. “What you want is a sustainable, balanced diet, where you can have treats when you want to, and it’s not a big buildup.” The one thing she insists on? You have to make it a mindful indulgence. So slow down, savor your food, and treat yourself to something you truly enjoy. That chocolate chip cookie is going to taste even better.