Can you survive without any carbohydrates in your diet? A group of social media influencers on the zero-carb diet seem to think so.
But what do real health experts, like registered dietitians, say about ketogenic diets, carnivore diets, and other very low-carb diets?
“Carbohydrates are absolutely necessary for you to feel your best and achieve good health,” says Daisy Mercer, a registered dietitian at MyFitnessPal.
Technically, you might be able to survive on a very low-carb diet, but that’s not the kind of healthy, balanced diet Mercer recommends.
“We need carbohydrates to function at our best and for many other body functions to function optimally,” Mercer says.
People are attracted to these very low-carb diets because they produce results quickly. Very low-carbohydrate diets may result in greater short-term weight loss than low-fat diets.
But does that mean you should put sweet potatoes and snacks on your pork chops? Here’s what you need to know about low-carb diets and health.
Are dietary carbohydrates absolutely necessary?
To fully answer this question, there are some nuances to understand.
Our bodies can actually produce carbohydrates in the form of glucose through a process called gluconeogenesis. If you don’t eat any dietary sources of glucose, your body uses other compounds to make glucose.
But remember, carbohydrates are the primary source of energy in the human diet. So while you can technically live without them, you probably won’t feel your best.
However, not all carbohydrates are created equal. “It’s important to choose the right carbohydrates (complex carbohydrates) that don’t digest too quickly so we can continue to release energy,” says Mercer. The ideal diet, she suggests, is one with a range of complex carbohydrates, plenty of lean protein and healthy fats.
Complex carbohydrates contain more fiber than simple carbohydrates, which are essentially just sugar. The latter is digested quickly, causing blood sugar changes and making you feel tired.
Because they contain fiber, complex carbohydrates take longer to break down, providing you with sustained energy and keeping you fuller longer.
What are the food sources of carbohydrates?
Rather than demonizing entire food groups, it’s best to understand how carbohydrates work so you can learn to reap their nutritional benefits while avoiding possible pitfalls. After all, many healthy foods are carbohydrates.
These include:
- Whole grains: Whole grains are rich in fiber, vitamins, minerals and other nutrients and have many health benefits. Whole grains include brown rice, quinoa, oats, whole wheat bread, barley and rye.
- fruits and vegetables: These carbohydrate powerhouses are a great source of vitamins and minerals. They also contain a lot of fiber. Apples, oranges, berries, sweet potatoes, peas and corn are just some of the fruits and vegetables that offer health benefits.
- Legumes: Beans, lentils, and peas are good sources of complex carbohydrates that are also rich in protein and fiber, which can keep you fuller longer.
You may want to limit one type of carbohydrate: simple carbohydrates or refined carbohydrates. These include foods made with refined sugar and flour. Think: white bread, packaged snacks, cookies, cakes and other sweets.
Can a diet with few or no carbohydrates allow the brain to function properly?
The effects of carbohydrate deficiency on the brain are unknown, but research is ongoing.
One short-term study compared people who ate a balanced diet with those who ate a low-carbohydrate diet.
Participants underwent a battery of cognitive tests. The low-carb group performed worse on memory tasks, but they also reported improved attention and less confusion.
Another small study of older adults with cognitive problems found that a high-fat, low-carbohydrate diet may modestly improve brain function and memory.
More research is needed to understand exactly how carbohydrate elimination affects the brain.
What is keto adaptation and what are the benefits?
The keto diet is named after ketones, which the body can use as an alternative fuel source when glucose is absent. When carbohydrate intake is very low (usually 20 grams to 50 grams per day), the liver uses fatty acids to produce ketones. This is called ketosis.
When on a no-carb or very low-carb diet, your body eventually enters a state called ketosis. In this metabolic state, your body functions by burning fat instead of carbohydrates for fuel.
Ketosis is an element of fat adaptation, which is the way your body adapts to using ketones instead of carbohydrates as its primary source of energy.
Research shows that people on a ketogenic diet may lose more weight than those on a low-fat diet.
But for most people, a diet of little or no dietary carbohydrates is difficult to maintain. There is no evidence that maintaining a state of ketosis is safe long-term. “Your body wants to burn carbs, but limiting carb intake isn’t always sustainable,” Mercer says.
In general, it’s important to listen to your body—if the ketogenic diet makes you feel tired, dizzy, or irritable, try adding some healthy carbs into your diet.
Interesting facts: There are 2,000 free recipes on the MyFitnessPal app. Get inspired and start tracking your meals today!
What are the potential risks of a zero-carb diet?
In the short term, you may experience brain fog and sluggishness when trying a zero-carb diet, Mercer says. Constipation and other digestive discomfort can also be a problem.
A zero-carb diet may pose other risks to your health in the long term. Low-carbohydrate diets, such as the ketogenic diet, may be associated with a twofold increase in the risk of “cardiovascular events” such as chest pain, clogged arteries, heart disease, and stroke.
These diets are also associated with:
- nutritional deficiencies
- kidney and liver problems
- mood swings
Counting macronutrients (macros) has become a popular way for people to find a better balance of carbohydrates, proteins, and fats. Tracking macros can help you achieve your health and weight loss goals.
What is the best weight loss diet?
There is no one-size-fits-all diet. The best way is to ask a nutritionist who can create a customized plan for you. Everyone will experience different results based on their individual metabolism, lifestyle, and health. Remember, before starting any new diet regimen, talk to your doctor to make sure it’s right for you.
bottom line
The human body has an amazing ability to recover. It’s technically possible to survive without eating carbs, but there’s no need to lose weight.
A more sustainable lifestyle involves cultivating a healthy relationship with food—including enjoying all foods in moderation.
You can use a food tracking app like MyFitnessPal to track your daily carb intake. You can easily count your macros and eat the right amount of carbs every day to feel good.
Originally published May 20, 2016; updated August 1, 2024
