It’s hard to recall a time when carbs were universally embraced, but the keto and paleo diet trends and concerns about highly-processed carbs have put this macronutrient in the hot seat for longer than many of us expected. The thing is: While there’s plenty of room for nuance and individual advice when it comes to healthy carb intake, our bodies always let us know when we’re not getting enough of them.

“Carbs have received a bad rap, which is a shame because carbohydrates have very important metabolic jobs in the body,” says dietitian Danielle Gaffen, M.S., R.D.N., L.D. “A lot of our initial energy comes from carbohydrates because they are the main source of energy for cells and the primary source of fuel for the brain.” They’re truly body and brain food.

Of course, everybody’s needs are unique—but nutritionists say that there are several signs you need to eat more carbs. Here’s what to look out for, plus how to get a better sense of your personal requirements.

Common signs you Need to Eat More Carbs

Whether you’re fully focused on low-carb eating or have been subconsciously slashing carb-filled foods because of diet culture messaging, you can bet your body will tell you if you’re taking the carb-cutting too far.

1. You Have Constant cravings

Having visions of donuts and bread loaves dancing in your head all day is one of the telltale signs you need to eat more carbs. “This is because when the brain senses low energy levels, it begins to send out hunger signals, encouraging us to seek out more energy,” says dietitian Stephanie Hnatiuk, R.D., C.D.E., P.T.S., who specializes in performance nutrition for runners. Often, these intense cravings crop up in the late afternoon and evening and send us spinning in search of chocolate, chips, or sugary beverages.

2. your workout performance Has Declined

Another indicator that you may want to increase your carbohydrate intake: struggling to make it through your workouts. “We might find we’re ‘running out of gas’ too early in a run, can’t maintain faster speeds, or get lightheaded and dizzy during HIIT workouts,” says Hnatiuk.

Read More: How To Get Past Your Muscle-Building Plateau

You see, if you don’t have enough carbohydrates stored in your muscles and liver to get you through tougher training sessions (which rely heavily on carbs), your blood sugar can drop too low, causing you to feel shaky, dizzy, or even nauseous. “Runners often refer to this as ‘hitting the wall’ or ‘bonking,’” she says. And if you’ve ever hit the wall during a workout, you certainly noticed.

3. You’re generally low on energy

Just as falling short on carbs leaves you feeling oomph-less in the gym, it can also make you feel rather zombie-like throughout the rest of your day. “It will likely be difficult to perform daily activities, especially those that are physical in nature,” says dietitian Shena Jaramillo, M.S., R.D. If hiking up the stairs or hauling groceries into the house starts to feel more exhausting than usual, you might be low on movement-fueling carbs.

4. You have brain fog

Did you just read the latest email to hit your inbox three times? Can’t seem to focus on that big work project you’re working on? Don’t know for the life of you where you left your keys? Of course, a whole slew of things can contribute to brain fog—but not getting enough of brain-powering carbohydrates is a common culprit. In fact, feeling fuzzy is one of the most common signs you need to eat more carbs.

“We often experience brain fog or even loss of memory on low-carb diets,” says Jaramillo. Remember that whole spiel about the brain primarily getting energy from carbohydrates? Your noggin can only work as hard as your fuel allows it to.

5. You experience menstrual cycle changes

For women, menstrual cycle changes definitely warrant a check-in with your healthcare provider to zoom in on what may be happening in your body—but not getting enough carbs can definitely lead to skipped periods or cycle irregularities. “Our bodies require fuel not only for daily exercise but also for normal body functions like digestion, brain function, and reproduction,” says Hnatiuk. “When our body isn’t receiving enough fuel, it needs to reduce unnecessary energy usage and the menstrual cycle may be impacted.” Basically, if your body has to choose whether to allocate the few carbs you give it to breathing and digestion or reproduction, you can bet it’ll choose the former.

How many carbs do you need?

“The Dietary Guidelines for Americans recommends that carbohydrates make up 45 to 65 percent of a person’s total daily calories,” says Gaffen. This means that if you follow a 2,000-calorie diet, 900 to 1,300 of those calories would come from carbohydrates. (That’s equivalent to 225 to 325 grams.) Of course, everyone’s overall calorie needs are different, so this is just a super-general baseline to keep in mind.

Other factors, such as physical activity level, also influence how many carbohydrates you need to feel and perform at your best. “The more active we are, the higher that percentage should be,” adds Hnatiuk. 

Ultimately, the best thing you can do to get a sense of your unique optimal carb intake level is to consult with a dietitian who can ensure that your eating habits are aligned with your health goals, lifestyle, and individual needs.

Read More: How To Pick The Perfect Pre-Workout Snack (That Won’t Wreck Your Stomach)

Once you’ve gotten a sense of how many carbs you need throughout the day, ensure your intake is as healthful and nourishing as possible by focusing on whole, fiber-rich foods (think fruits, whole grains, starchy vegetables, and pulses), suggests Hnatiuk. “These foods provide not only fuel, but fiber and essential vitamins and minerals that help to optimize our health and performance,” she says. “They also help to keep us full for longer, which is key for avoiding excessive hunger and overeating.”

Yep, that also means minimizing highly-processed and refined carbs, such as white breads and pastas, cookies, and crackers.

If you have certain health concerns or conditions that might influence when and how you consume carbs, such as diabetes, chat with your dietitian about how you can optimize not only how many carbs you eat but how you eat them, too. (Sign up for a free virtual consultation with one of The Vitamin Shoppe’s nutritionists.)