A no-carb diet is an extreme version of low-carb dieting. It eliminates almost all carbs, including whole grains, fruits, and most vegetables.
While studies show that decreasing your carb intake can help you shed pounds and may have health benefits, eliminating carbs is highly restrictive and most likely unnecessary.
This article provides a detailed overview of a no-carb diet, including its potential benefits, downsides, and foods to eat and avoid.
What is a no-carb diet?
A no-carb diet is a way of eating that eliminates digestible carbs as much as possible.
Carbs are your body’s primary source of energy. They’re found in grains, beans, legumes, fruits, vegetables, milk, yogurt, pasta, bread, and baked goods.
Therefore, someone on a no-carb diet must avoid most of these foods and instead eat foods that contain primarily protein or fat, such as meats, fish, eggs, cheese, oils, and butter.
There is no strict rubric for a no-carb diet. Some people who follow it eat nuts and seeds, non-starchy vegetables, and high-fat fruits like avocado and coconut.
Even though these foods have some carbs, they’re high in fiber. Therefore, they have only a minuscule number of digestible or net carbs, which is calculated by subtracting the amount of fiber from the total number of carbs.
A no-carb diet resembles a ketogenic diet, which limits your carb intake to fewer than 30 grams per day and encourages you to get 70% or more of your daily calories from fat.
Depending on what you choose to eat, a no-carb diet can be more restrictive than keto.
Summary: A no-carb diet largely bans carbs, instead encouraging foods that are primarily comprised of protein and fat. In some cases, you can eat high-fiber foods as well.
How to follow a no-carb diet
Some online sources recommend keeping your net carb intake to 20–50 grams per day on a no-carb diet, but there are no specific macronutrient ranges or any set protocol.
Simply put, when you follow a no-carb diet, you avoid all high-carb foods.
Specifically, you should eliminate whole and refined grains, baked goods, fruits, milk, yogurt, beans, legumes, pasta, bread, sugar-sweetened beverages, and starchy vegetables like peas and corn.
Food and drinks allowed on a no-carb diet include meat, fish, eggs, cheese, butter, oils, water, and plain coffee or tea.
If you’re less stringent, you can also eat nuts, seeds, non-starchy vegetables, and high-fat fruits like avocado and coconut since these foods are low in net carbs.
Since this diet focuses on restricting a specific macronutrient, there are no recommendations for daily calorie intake or portion sizes.
Summary: A no-carb diet eliminates all carb-rich foods like grains, baked goods, and fruits, instead encouraging foods high in protein and fat.
Can a no-carb diet help you lose weight?
In general, reducing your carb intake can help you lose weight.
Replacing carbs with protein or fat can help you feel more full and eat fewer overall calories, which in turn promotes weight loss.
In addition, very low-carb diets typically promote rapid weight loss in the first few weeks due to a quick drop in water weight. This is because every gram of carbs holds approximately three grams of water in your body.
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A study in 79 obese adults found that over 6 months, those who restricted carb intake to fewer than 30 grams per day lost around 8.8 pounds (4 kg) more than those who instead restricted fat to fewer than 30% of daily calories.
Other studies offer similar results and suggest that following a very low carb or ketogenic diet for more than 12 months can result in more sustained weight loss compared to low-fat diets.
However, the research is mixed. Some studies have found that low-carb diets are no more effective for long-term weight loss than other eating methods that also reduce overall calorie intake, such as low-fat diets.
With these results in mind, following a no-carb diet would likely result in weight loss — at least in the short term.
Still, you do not need to eliminate carbs to achieve weight loss. Gradually reducing your carb intake and, more importantly, decreasing your overall calorie intake are less restrictive ways to lose weight.
Summary: A low-carb diet that’s high in filling protein and fat can help decrease your overall calorie intake and lead to weight loss. Nonetheless, a no-carb diet is not necessary to achieve these results.
Other benefits of a no-carb diet
No studies exist on diets that eliminate carbs, but research on very low-carb and ketogenic diets suggests that they may have several benefits.
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May benefit heart health
Decreasing your carb intake may improve heart health.
In particular, very low-carb diets have been shown to decrease blood triglyceride levels. Elevated triglyceride levels can increase your risk of heart disease.
One study in 29 overweight men found that reducing carb intake to 10% of daily calories for 12 weeks decreased triglyceride levels by 39%, compared to baseline levels.
Other studies suggest that very low-carb diets may also increase levels of HDL (good) cholesterol, which can help protect against heart disease.
Even so, more research is needed.
May lead to better blood sugar control
Cutting carbs — particularly refined carbs and sugar — can aid blood sugar control, which may be especially helpful for people with diabetes.
Some studies show that low-carb and keto diets are effective in reducing blood sugar levels.
A 6-month study in 49 obese adults with type 2 diabetes found that those who followed a keto diet had significantly greater reductions in hemoglobin A1c — a measure of average blood sugar — than those who didn’t eat a keto diet.
Reducing carb intake can prevent spikes in blood sugar and may thus help prevent diabetes complications. Yet, it’s not necessary to completely exclude carbs from your diet. Diabetes can be controlled on higher-carb diets, too.
Other possible benefits
Other possible benefits of very-low-carb diets include:
- Lower blood pressure. Some studies suggest that reducing your carb intake can help lower blood pressure.
- Reduction of belly fat. Limited research indicates that very-low-carb diets are better than low-fat diets at decreasing belly fat, a type of fat associated with inflammation and certain diseases.
- Lower risk of metabolic syndrome. Decreasing carb intake may help prevent some of the risk factors associated with metabolic syndromes, such as high blood pressure, elevated blood sugar, and belly fat.
Summary: Eating a very low-carb diet may help improve heart health and blood sugar control. However, it’s unnecessary to completely cut carbs to experience these benefits.
Downsides of a no-carb diet
A no-carb diet may have several downsides.
A no-carb diet may cause constipation and low energy
Since a no-carb diet restricts fruits, most vegetables, beans, and whole grains, it can be very low in fiber.
Fiber is important for digestion since it helps maintain bowel regularity. Because of this, a no-carb diet may lead to constipation and digestive discomfort.
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What’s more, carbs are your body’s primary source of energy. Therefore, a no-carb diet may lead to low energy and fatigue, especially in the beginning.
The metabolic changes that occur in your body when you cut carbs can also cause poor mental function, nausea, and disrupted sleep in the short term.
A no-carb diet may lack some nutrients
A no-carb diet may not provide enough vitamins and minerals, such as potassium, B vitamins, and vitamin C, which are abundant in fruits, vegetables, and other plant foods.
Additionally, the increased urination that results from restricting carbs may lead to deficiencies in sodium and potassium over time.
Eating a balanced diet with a variety of foods can help ensure that you get enough of the nutrients you need. Additionally, it’s more sustainable than a no-carb diet in the long term.
A no-carb diet is highly restrictive with unknown long-term effects
Insufficient studies exist on the long-term effects of very-low-carb diets, so it’s especially difficult to estimate the long-term effects of a no-carb diet.
Due to this lack of research, following a no-carb diet over a long period could have severe health consequences.
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As a no-carb diet is highly restrictive, very high in fat, and not well researched for safety, it’s not appropriate for those with eating disorders, children, cholesterol hyper-responders, and pregnant or breastfeeding women.
Summary: A no-carb diet restricts foods with fiber and most plant foods that are rich in vitamins and minerals. This may lead to constipation, low energy, and possible micronutrient deficiencies.
Foods to eat on a no-carb diet
Foods that are typically allowed on a no-carb diet include:
- Meat and low-carb animal products: chicken, beef, turkey, lamb, venison, bison, pork, eggs, butter, lard, cheese
- Seafood: salmon, tilapia, cod, shrimp, sardines, herring, crab
- Seasonings: herbs and spices
- Zero-calorie beverages: water, black coffee, and plain tea
- Nuts and seeds (those low in net carbs): almonds, walnuts, pumpkin seeds, sunflower seeds, pistachios, cashews
- Non-starchy vegetables (those low in net carbs): broccoli, zucchini, bell peppers, cauliflower, leafy greens, rutabaga, turnips, Brussels sprouts, asparagus, mushrooms
- High-fat fruits: coconut, avocado
Summary: A no-carb diet restricts foods that are high in carbs and relies primarily on meat, dairy, seafood, and low-carb plant foods.
Foods to avoid on a no-carb diet
A no-carb diet is highly restrictive and eliminates several food groups, such as:
- Grains: rice, farro, barley, quinoa, wheat, bread, pasta
- Sweets and baked goods: cakes, cookies, candy, sodas, sugary drinks
- Fruits: apples, oranges, bananas, berries, kiwi, pears
- Starchy vegetables: peas, corn, squash, potatoes
- Beans and legumes: black beans, kidney beans, chickpeas, lentils
- Dairy: milk and yogurt
- Condiments with added sugar: ketchup, barbecue sauce, salad dressings
- Alcohol: beer, wine, liquor, sugary mixed drinks
Summary: Restricted foods on a no-carb diet include grains, sweets, baked goods, fruits, starchy vegetables, beans, milk, yogurt, and alcohol.
Sample menu for the no-carb diet
Here is a sample five-day menu for a no-carb diet.
- Breakfast: eggs, bacon, sliced avocado
- Lunch: romaine lettuce with ground turkey, cheese, and olive oil dressing
- Dinner: salmon, zucchini noodles, side of sunflower seeds
- Snacks: beef jerky, cheese
- Breakfast: eggs, steak, bell pepper strips
- Lunch: tuna-fish lettuce wraps, carrots dipped in mashed avocado
- Dinner: lamb chops, spinach salad with walnuts and olive oil dressing
- Snacks: hard-boiled eggs, pistachios
- Breakfast: eggs, turkey sausage, avocado
- Lunch: scallops, Brussels sprouts roasted with Parmesan cheese
- Dinner: pork chops, roasted tomatoes, and turnips
- Snacks: sunflower seeds, brie
- Breakfast: eggs with shredded chicken, jalapeño, cheddar cheese
- Lunch: turkey burger patties with rutabaga fries
- Dinner: meatballs and zucchini noodles with roasted tomatoes
- Snacks: sardines, macadamia nuts
- Breakfast: cheesy eggs with broccoli, chicken sausage
- Lunch: flank steak and arugula salad with olive oil dressing, cashews
- Dinner: coconut-crusted shrimp, roasted asparagus, and mushrooms
- Snacks: turkey jerky, avocado
Summary: A no-carb diet is very restrictive and mainly relies on animal foods and very low-carb plant foods.
A no-carb diet eliminates almost all carbs and encourages high intakes of fat and protein.
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It may boost weight loss, heart health, and blood sugar control. Yet, it’s unnecessary to cut all carbs to experience these benefits.
Plus, this diet may reduce energy levels and increase your risk of nutrient deficiencies.
Instead, aim to eat a balanced diet with a variety of foods.