Low-carb diets have been popular for decades.
They used to be highly controversial but have recently gained mainstream acceptance.
Low-carb diets tend to cause more weight loss than low-fat diets — at least in the short term ().
They also improve numerous health markers, such as blood triglycerides, HDL (good) cholesterol, blood sugar, and blood pressure (, , , , ).
However, many types of this eating pattern exist.
Here are 8 popular ways to do a low-carb diet.
The typical low-carb diet does not have a fixed definition.
It is simply referred to as a low-carb or carb-restricted diet.
This eating pattern tends to be lower in carbs and higher in protein than a typical Western diet. It usually emphasizes meats, fish, eggs, nuts, seeds, vegetables, fruits, and healthy fats.
You’re meant to minimize your intake of high-carb foods like grains, potatoes, sugary drinks, and high-sugar junk foods.
The recommended carb intake per day generally depends on your goals and preferences. A common rubric might be something like this:
- 100–150 grams. This range is meant for weight maintenance or frequent high-intensity exercise. It gives room for plenty of fruit and even some starchy foods like potatoes.
- 50–100 grams. This range is intended for slow and steady weight loss or weight maintenance. There's room for plenty of vegetables and fruit.
- Under 50 grams. This is geared toward fast weight loss. Eat plenty of vegetables but limit fruit intake to berries low on the glycemic index (GI).
SUMMARY Your typical low-carb diet is much lower in carbs and higher in protein than a regular diet. The recommended carb intake depends on individual goals and preferences.
The ketogenic diet is a very-low-carb, high-fat diet.
The goal of a keto diet is to keep carbs so low that your body goes into a metabolic state called ketosis.
In this state, your insulin levels plummet and your body releases large amounts of fatty acids from its fat stores.
A lot of these fatty acids are transferred to your liver, which turns them into ketones. Ketones are water-soluble molecules that can cross the blood-brain barrier and supply energy to your brain.
Then, instead of running on carbs, your brain starts relying largely on ketones. Your body can produce the small amount of glucose still required by your brain via a process called gluconeogenesis.
Some versions of this diet even restrict protein intake because too much protein may reduce the number of ketones you produce.
Traditionally used to treat drug-resistant epilepsy in children, the keto diet may also have benefits for other neurological disorders and metabolic problems like type 2 diabetes (7, , , ).
It has also become popular for fat loss — even among some bodybuilders — as it’s a very effective way to lose fat and tends to cause a major reduction in appetite (, ).
A ketogenic diet involves high-protein, high-fat foods. Carbs are generally limited to fewer than 50 — and sometimes as few as 20–30 — grams per day.
A conventional keto eating pattern is referred to as a standard ketogenic diet (SKD).
However, there are other variations that involve strategically adding carbs:
- Targeted ketogenic diet (TKD). In this version, you add small amounts of carbs around workouts.
- Cyclical ketogenic diet (CKD). This type has you eat a ketogenic diet on most days but switch to a high-carb diet for 1–2 days each week.
SUMMARY A ketogenic (keto) diet involves reducing carbs sufficiently to induce a metabolic state called ketosis. It’s a very powerful diet to lose fat and may protect against several diseases.
It focuses mostly on meats, fish and shellfish, eggs, healthy fats, vegetables, dairy products, nuts, and berries.
The recommended carb intake on this diet can range from 20–100 grams per day.
SUMMARY The LCHF diet is a very-low-carb eating pattern that focuses mostly on whole, unprocessed foods.
The paleo diet is currently one of the world's most popular ways of eating. It encourages eating foods that were likely available in the Paleolithic era — before the agricultural and industrial revolutions.
According to paleo proponents, returning to the diet of your prehistoric ancestors should improve health because humans allegedly evolved and adapted to eating such foods.
Several small studies show that a paleo diet can cause weight loss, reduce blood sugars, and improve risk factors for heart disease (, , ).
A paleo diet is not low-carb by definition but tends to be so in practice.
It emphasizes meats, fish, seafood, eggs, vegetables, fruits, tubers, nuts, and seeds. A strict paleo diet eliminates processed foods, added sugar, grains, legumes, and dairy products.
There are several other popular versions, such as the primal blueprint and perfect health diets. All of them tend to be much lower in carbs than a typical Western diet.
SUMMARY The paleo diet involves eating unprocessed foods that were likely available to your Paleolithic ancestors. While not strictly low-carb, it can be modified to fit such a lifestyle.
The Atkins diet is the best-known low-carb eating plan. It involves reducing all high-carb foods while eating as much protein and fat as desired.
The diet is split into four phases:
- Phase 1: Induction. Eat under 20 grams of carbs per day for 2 weeks.
- Phase 2: Balancing. Slowly add more nuts, low-carb vegetables, and fruit.
- Phase 3: Fine-tuning. When you get close to your weight goal, add more carbs until your weight loss becomes slower.
- Phase 4: Maintenance. Eat as many healthy carbs as your body tolerates without gaining back the weight you lost.
The Atkins diet was originally demonized, but current research indicates it’s both safe and effective as long as fiber intake is adequate. This diet is still popular today.
SUMMARY The Atkins diet has been popular for over 40 years. It is a 4-phase, low-carb eating pattern that allows you to consume plenty of fat and protein.
A diet termed Eco-Atkins is essentially a vegan version of the Atkins diet.
It includes plant foods and ingredients that are high in protein and/or fat, such as gluten, soy, nuts, and plant oils.
About 25% of its calories come from carbs, 30% from protein, and 45% from fat.
As such, it’s higher in carbs than a typical Atkins diet — but still much lower than a typical vegan diet.
One six-month study showed that an Eco-Atkins diet caused more weight loss and greater improvement in heart disease risk factors than a high-carb vegetarian diet ().
SUMMARY The Eco-Atkins diet is a vegan version of the Atkins diet. While higher in carbs than a typical Atkins diet, it’s still very low-carb compared to most vegetarian and vegan diets.
Some people prefer to eliminate all carbs from their diet.
This is called a zero-carb diet and usually includes only animal foods.
People who follow a zero-carb diet eat meat, fish, eggs, and animal fats like butter and lard. Some of them also add salt and spices.
There are no recent studies that show a zero-carb diet to be safe. Only one case study — from 1930 — exists, in which two men ate nothing but meat and organs for a year but appeared to remain in good health (17).
A zero-carb diet is lacking in some important nutrients, such as vitamin C and fiber. For this reason, it is generally not recommended.
SUMMARY Some people follow a zero-carb diet, which excludes all plant foods. No quality studies have been done on this eating pattern, and it is usually discouraged.
The Mediterranean diet is very popular, especially among health professionals.
It is based on the traditional foods of Mediterranean countries earlier in the 20th century.
A low-carb Mediterranean eating pattern is modeled after its namesake diet but limits higher-carb foods like whole grains.
Unlike a regular low-carb diet, it emphasizes more fatty fish instead of red meat and more extra virgin olive oil instead of fats like butter.
A low-carb Mediterranean diet may be better for heart disease prevention than other low-carb diets, although this needs to be confirmed in studies.
SUMMARY A low-carb Mediterranean diet is similar to a regular low-carb diet. However, it includes more fish and extra virgin olive oil.