Low-carb diets are incredibly powerful.

They may help reverse many serious illnesses, including obesity, type 2 diabetes, and metabolic syndrome.

However, some myths about this diet are perpetuated by the low-carb community. Many of these notions are not backed by science.

Here are 10 common myths about low-carb diets.

1. Low-carb diets work for everyone

Studies consistently show that low-carb diets aid weight loss and improve most risk factors for disease (1, 2, 3).

That said, this eating pattern is not appropriate for everyone.

Some people may simply feel unwell on the diet, while others don’t get the results they expect.

Notably, athletes and people who are physically active need significantly more carbs than this diet can provide.

SUMMARY Low-carb diets can promote weight loss and improve health for many people. However, this may not apply to everyone — particularly athletes.

2. Carbs are inherently fattening

A high intake of sugar and refined carbs harms your health.

Still, carbs are only fattening if they’re refined and included in foods that are highly palatable and easy to overeat.

For example, baked potatoes have plenty of fiber and help you feel full — whereas potato chips are deep-fried in corn oil and seasoned with salt, making them heavily processed and addictive.

Keep in mind that many populations around the world, such as inhabitants of the Japanese island of Okinawa, maintain good health on a high-carb diet that includes whole, unprocessed foods.

SUMMARY While overeating any calorie-dense nutrient will cause weight gain, carbs themselves aren’t fattening if included in a balanced diet based on whole foods.

3. Carrots, fruits, and potatoes are unhealthy because of the carbs

Many real, traditional foods are demonized by low-carbers because of their carb content.

These include foods like fruits, whole potatoes, and carrots.

It is essential to limit these foods on a very low-carb, ketogenic diet — but this does not mean that there is anything wrong with those foods.

In nutritional science, as in most disciplines, context is important.

For example, it would be a health improvement to replace any junk food in your diet with high-carb, ripe bananas. However, for people with diabetes trying to cut carbs, adding bananas to their diet may be harmful.

SUMMARY Although you should limit your intake of whole, high-carb fruits and vegetables on a low-carb diet, these foods can still be a healthy component of a balanced diet.

4. Low-carb diets should always be ketogenic

A ketogenic diet is a very-low-carb diet, usually consisting of fewer than 50 grams of carbs per day alongside a very high fat intake (60–85% of calories).

Ketosis can be a highly beneficial metabolic state, especially for people with certain diseases like diabetes, metabolic syndrome, epilepsy, or obesity (4, 5, 6).

However, this isn’t the only way to follow a low-carb diet.

This eating pattern can include 100–150 grams of carbs per day — and perhaps more.

Within this range, you can easily eat several pieces of fruit per day and even small amounts of whole, starchy foods like potatoes.

While a very-low-carb, ketogenic diet may be the most effective for quick weight loss and several illness symptoms, it doesn’t work for everyone.

SUMMARY A low-carb diet doesn’t have to be ketogenic. For those who don’t feel like going on keto, a general low-carb diet can still provide many benefits.

5. All carbs are sugar

Claiming that all carbs are broken down into sugar in the digestive system is partly true — but misleading.

The word “sugar” applies to various simple sugars like glucose, fructose, and galactose. Table sugar (sucrose) consists of one molecule of glucose connected to fructose.

Starch, which is found in grains and potatoes, is a long chain of glucose molecules. Digestive enzymes break starch down into glucose before absorption.

In the end, all carbs (excluding fiber) end up as sugar.

While simple sugars are easily digestible and cause a significant rise in blood sugar levels, starches and other carbs in whole foods don’t tend to raise blood sugar levels as much as those in desserts and refined or processed foods.

Therefore, it’s important to distinguish between whole foods and refined carbs. Otherwise, you might believe that there’s no nutritional difference between a potato and a candy bar.

SUMMARY All digestible carbs are absorbed into your bloodstream in the form of simple carbs or sugar. However, digesting complex carbs takes time, resulting in a slower and lower rise in blood sugar levels.

6. It’s impossible to gain weight on a low-carb diet

Some people believe that weight gain is impossible as long as carb intake and insulin levels are kept low.

Yet, it’s very possible to gain weight on a low-carb diet.

Many low-carb foods can be fattening, especially for those who are prone to binge eating.

These include cheese, nuts, peanuts, and heavy cream.

Although many people can eat these foods without any problems, others need to moderate their intake if they want to lose weight without restricting calories.

SUMMARY While going on a low-carb diet generally promotes weight loss, some people may still need to moderate their intake of high-fat foods.

7. Drinking butter and coconut oil is a good idea

Despite decades of anti-fat propaganda, studies suggest that saturated fat is not as harmful as previously assumed (7, 8, 9).

There is no reason to avoid high-fat dairy products, fatty cuts of meat, coconut oil, or butter. In moderation, these are healthy foods.

However, overconsumption can be dangerous.

While it may be trendy to add heaps of butter and coconut oil to your coffee, doing so gives you less leeway to include other healthy, nutrient-dense foods in your diet.

SUMMARY While eating foods high in saturated fat is fine in moderation, avoid including too much in your diet. Instead, choose plenty of whole foods rich in protein and fiber.

8. Calories don’t matter

Some low-carb advocates assert that calorie intake doesn’t matter.

Calories are a measure of energy, and body fat is simply stored energy.

If your body takes in more energy than you can burn off, you store it as body fat. If your body expends more energy than you take in, you burn fat for energy.

Low-carb diets work partly by reducing appetite. As they make people eat fewer calories automatically, there’s little need for calorie counting or portion control (10, 11).

While calories matter in many cases, rigorously counting them is largely unnecessary on a low-carb diet.

SUMMARY Low-carb diets promote weight loss partly by reducing appetite and calorie intake. Yet, calories still matter for many other diets.

9. Fiber is mostly irrelevant to human health

Indigestible carbs are collectively known as dietary fiber.

Humans don’t have the enzymes to digest fiber, but this nutrient is far from irrelevant to your health.

It’s vital for your gut bacteria, which turn fiber into beneficial compounds like the fatty acid butyrate (12).

In fact, many studies show that fiber — especially soluble fiber — leads to various benefits, such as weight loss and improved cholesterol (13, 14, 15).

Thus, it’s not only simple but healthy to eat fiber-rich plant foods on a low-carb diet.

SUMMARY Fiber is a very important component of a healthy diet. You can easily eat plenty of fiber-rich plant foods on a low-carb diet.

10. Carbs cause disease

Many people who are metabolically healthy can eat plenty of carbs without harm, as long as they focus on whole foods.

However, for people with insulin resistance or obesity, the body’s metabolic rules seem to change.

People who have metabolic dysfunction may need to avoid all high-carb foods.

Keep in mind that even though removing most carbs may be necessary to reverse a disease, it does not mean that carbs themselves caused the illness.

If you don’t have metabolic dysfunction, it’s fine to eat high-carb foods — as long as you stick to whole, unprocessed foods and exercise regularly.

SUMMARY Although going on a low-carb diet helps many people lose weight and improve their health, it doesn’t mean that a high-carb lifestyle can’t be healthy as well. It just depends on the individual, as well as the context.

The bottom line

While low-carb diets can promote weight loss and aid numerous health conditions, many myths about them abound.

Overall, these diets aren’t meant for everyone.

If you want to help control a metabolic condition or lose weight quickly, it’s fine to try a low-carb diet. At the same time, this eating pattern isn’t necessarily any healthier than a lifestyle that combines whole foods with enough exercise.