Have you ever heard the blanket advice to avoid sugar and other carbohydrates if you want to be healthy?

This red flag is one of many examples of diet culture, a system of beliefs that promotes certain bodies and ways of eating while demonizing others (and oppresses people who fit into the latter category). It likes to make us think that carbs (and other macronutrients) are not good for us, no questions asked.

Dietitians have something to say about that. Their belief is a bit different, especially for athletes and other people who exercise. Below, they explain some of the myths and truths they want everyone to know.

The No. 1 myth about carbs and sugar? They’re all ‘bad’ or ‘unhelpful.’

Dietitians could go on for days about food myths — especially when it comes to carbs and sugar — but many of these relate to one misconception: that carbs and sugars are all “bad” or “unhelpful” for your body.

Sure, too much sugar is not good for you. A recent review of meta-analyses in the journal BMJ noted that dietary sugar consumption is associated with negative health outcomes such as diabetes, high blood pressure, heart disease, cancer, dental erosion, depression and more. Listening to your body, or practicing so-called intuitive eating, and eating enough each day may help with restricting excess sugar intake.

But sugars can still have value — more than we often hear about.

“They are our body’s life force,” said Jessica Jaeger, a registered dietitian and private practice owner who specializes in eating disorders, intuitive eating and sports nutrition.

She added that restricting carbs can lead to undernourishment, fatigue, moodiness, gastrointestinal disturbances, altered hormone production and much more.

“Carbs and sugar have been wrongfully demonized for years, but the reality is that we can rarely declare a food group or macronutrient good or bad,” agreed Cara Harbstreet, a registered dietitian with experience in sports nutrition. “Nutrition is much more nuanced than that.”

This point is especially important for athletes (or anyone else who exercises). Sarah Schlichter, a “non-diet” dietitian who specializes in sports nutrition, said that carbohydrates are “preferred” for those who work out. She added that carbs can also provide vitamins, minerals and fiber.

Carbs and sugar can help you exercise.

Glucose is the preferred source of energy for your body and brain.

Glucose, a type of sugar, is found in carbs — and our bodies and brains love it.

“Your brain, organs and skeletal muscle all function better when properly fueled, especially during high-intensity endurance exercise,” Harbstreet said.

“While it’s possible to tap into reserves of fat, it’s a less efficient metabolic pathway and thus takes time and training. At the end of the day, simple carbohydrates (aka sugar) can help you perform your best and feel better while doing it.”

Carbs are stored as glycogen in the muscles and liver, which can strengthen performance.

Enough said, right?

“If an athlete does not consume adequate amounts of carbohydrates, their glycogen stores will be depleted, and their performance therefore potentially compromised,” Jaeger said.

So without carbs, your ability to go full out during a workout may suffer.

The body can digest glucose and carbs quickly.

This relatively fast digestion process is helpful for two reasons.

First, it reduces the risk of gastrointestinal distress while you’re working out, according to Harbstreet.

Second, it allows the body to reap and utilize energy more quickly.

“Carbohydrates are broken down into glucose, which is the quickest fuel for contracting muscles and uses less oxygen than other food sources, making it a more efficient fuel source for work,” Schlichter said.

“Increased glucose availability in the muscle also helps the body prevent low blood sugar bouts during exercise and aids in performance because that fuel is available almost instantaneously, compared to breaking down fat or protein.”

Carbs and sugars support hydration.

It’s true: Your rehydration game isn’t as strong without some carbs and sugars. Like registered dietitian Anna Sweeney wrote in an Instagram post, “electrolytes without carbs are a no.”

“Carbohydrates help the body absorb water due to their water-loving molecular structure,” Jaeger said.

Basically, carbs assist salt and water with getting into the bloodstream, Schlichter explained, and sugar intake can balance blood sugar, which may stimulate appetite and thirst, preventing further dehydration.

“Pairing sodium and other electrolytes with fluids and glucose is a quick way to rehydrate at the molecular level,” Harbstreet added. “This, rather than simply gulping down more water, is what supports the kind of fluid balance that will help you feel better and perform better.”

How many carbs do you need?

Not sure if you’re eating enough carbs and sugar to fuel your body and workout? Consider how you feel physically and mentally.

“You should feel focused, energized (even if you’re fatigued from training or racing) and able to recover before your next training session,” Harbstreet said. “While feeling hungry is quite normal, you shouldn’t feel ravenous, overly hungry or depleted.”

Schlichter shared some signs that you might not be eating enough carbs, such as feeling hungry often, not recovering from workouts, feeling like you’re underperforming, having a low blood sugar, thinking about food often, waking up hungry during the night, getting injured often, losing hair and experiencing a loss of menstruation.

Jaeger said everybody is different, so she recommended talking to a sports dietitian for individualized recommendations, as well as consuming carbohydrates regularly. “Athletes should consume carbohydrates with most, if not all, meals and snacks,” she said.

What types of carbs are the best for workouts?

Food can help maximize your workout and the pleasure you take in it. For best results, dietitians agreed that simple, low-fiber carbohydrates are best before and during workouts to reduce the likelihood of gastrointestinal distress, while complex carbs (plus a protein) are best afterward to support recovery.

Schlichter said simple carbs can typically be found in fruits, bagels, waffles, white bread, electrolyte drinks (with sugar), juice and crackers, for example.

Complex carbs can be found in beans, potatoes, corn, green peas, oats, brown rice and quinoa, among other things. If you aren’t hungry after a workout, Harbstreet recommended opting for an easy-to-consume option, like a protein recovery shake or even chocolate milk.

“There are pros and cons to choosing whole-food sources of carbs versus sports nutrition, but don’t be afraid to experiment and find what works for you,” Harbstreet said. “Generally, something will be better than nothing.”

Again, carbs and sugar are important for all of us, though, not just athletes. Our bodies are constantly working, burning calories and energy even when we don’t realize it.