What is ketosis?
Ketosis is a process that occurs when your body uses fat as its main fuel source. Normally, your body uses blood sugar (glucose) as its key energy source.
You typically get glucose in your diet by eating carbohydrates (carbs) such as starches and sugars. Your body breaks the carbohydrates down into glucose and then uses the glucose as fuel. Your liver stores the rest and releases it as needed.
When your carb intake is very low, these glucose stores drain down. Since your body doesn’t have enough carbs to burn for energy, it burns fat instead. As your body breaks down fat, it produces a compound called ketones. The ketones, or ketone bodies, become your body and brain’s main source of energy.
The fat your body uses to create ketones may come from your diet (nutritional ketosis), or it may come from your body’s fat stores. Your liver produces a small amount of ketones on its own. But when your glucose level decreases, your insulin level decreases. This causes your liver to ramp up the production of ketones to ensure it can provide enough energy for your brain. Therefore, your blood has high levels of ketones during ketosis.
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What is the ketosis diet?
The ketogenic (keto) diet changes the way your body uses food. Typically, carbohydrates in your diet provide most of the fuel your body needs. The keto diet reduces the number of carbs you eat and teaches your body to burn fat for fuel instead.
The keto diet is high in fat, moderate in protein and low in carbohydrates. The standard keto diet consists of 70% to 80% fats, 10% to 20% proteins and 5% to 10% carbohydrates.
Many nutrient-rich foods contain high amounts of carbohydrates. This includes whole grains, fruits and vegetables. Carbs from all sources are restricted on the keto diet. So you’ll have to cut out all bread, cereal and other grains and make serious cuts to your fruit and vegetable intake. The types of foods that provide fat for the keto diet include:
- Meats and fish.
- Eggs.
- Nuts and seeds.
- Butter and cream.
- Cheese.
- Oils such as olive oil and canola oil.
How many carbs do I need for ketosis?
You’ll need to stay under 50 grams of carbohydrates per day to enter and stay in ketosis. That’s about three slices of bread, two bananas or 1 cup of pasta.
How long does it take to get into ketosis?
If you eat between 20 and 50 grams of carbohydrates each day, it will usually take you two to four days to enter ketosis. However, the time it takes to enter this state varies based on several factors. It may take you a week or longer to get into ketosis. Factors that may influence how long it takes you to achieve this state include your:
- Age.
- Carbohydrate, fat and protein intake.
- Physical activity level.
- Metabolism.
- Sleep health.
- Stress level.
If you eat a high-carb diet before starting a keto diet, it may take you longer to reach ketosis than someone who consumes a low-carb diet. That’s because your body needs to exhaust its glucose stores first.
You may be able to get into ketosis faster with intermittent fasting. The most common method of intermittent fasting involves eating all of your food within eight hours. Then, you fast for the remaining 16 hours of a 24-hour period.
What are the benefits of ketosis?
Research has shown that ketosis may have several health benefits. One of the biggest benefits of ketosis may be weight loss. The process can help you feel less hungry, which may lead to eating less food. It can help you lose belly fat (visceral fat) while maintaining a lean mass. Other possible benefits of ketosis include treating and managing diseases such as:
- Epilepsy: Healthcare providers often put children with epilepsy on the keto diet to reduce or even prevent seizures by altering the “excitability” part of their brain.
- Other neurologic conditions: Research has shown the keto diet may help improve neurological conditions such as Alzheimer’s disease, autism and brain cancers such as glioblastoma.
- Type 2 diabetes: The keto diet can help people with Type 2 diabetes lose weight and manage their blood sugar levels.
- Heart disease: The keto diet may lower your risk of developing cardiovascular disease by lowering your blood pressure, improving your HDL (“good”) cholesterol levels and lowering your triglycerides.
- Metabolic syndrome: The keto diet may reduce your risk of developing metabolic syndrome, which is associated with your risk of heart disease.
Ketosis has also been shown to increase your focus and energy. The keto diet delivers your body’s energy needs in a way that reduces inflammation. Research suggests your brain works more efficiently on ketones than on glucose.
What are the side effects of ketosis?
The keto diet has many benefits, but it may come with some side effects. One of the signs of ketosis may include “keto flu,” which includes symptoms such as upset stomach, headache and fatigue. Other symptoms of ketosis may include:
- Bad breath (“keto” breath).
- Constipation.
- Insomnia.
- Dehydration.
- Low bone density (osteopenia) and bone fractures.
- High cholesterol (hyperlipidemia).
- Kidney stones.
FAQs
Ketosis is a metabolic state that occurs when your body burns fat for energy instead of glucose. The keto diet has many possible benefits including potential weight loss, increased energy and treating chronic illness. However, the diet can produce side effects including “keto” breath and constipation.
What are the side effects of ketosis? ›
Common short-term side effects resulting from the initiation of KD have been referred to as “keto flu,” which encompasses symptoms including fatigue, headache, dizziness, nausea, vomiting, constipation, and low exercise tolerance [6].
What are the benefits of ketosis? ›
Ketosis is a metabolic state that you can achieve by following a ketogenic diet. Possible benefits of ketosis include weight loss, improved blood sugar management, and reduced seizures in children with epilepsy.
What happens when your body is in ketosis? ›
Ketosis is a process that happens when your body doesn't have enough carbohydrates to burn for energy. Instead, it burns fat and makes things called ketones, which it can use for fuel. Ketosis is a word you'll probably see when you're looking for information on diabetes or weight loss.
How long can you stay in ketosis safely? ›
Gulotta recommends staying on keto for six months max before reintroducing more carbs to your diet. And Scott Keatley, RDN, of Keatley Medical Nutrition Therapy in New York City, agrees: “The science hasn't gotten to the point where I would be comfortable recommending it as a forever diet,” he says.
Is there a downside to ketosis? ›
Keto is not safe for those with any conditions involving their pancreas, liver, thyroid or gallbladder. Someone new to the keto diet can also experience what's called the “keto flu” with symptoms like upset stomach, dizziness, decreased energy, and mood swings caused by your body adapting to ketosis.
What organ does ketosis affect? ›
This shift involves increasing fatty acid oxidation and production of ketones in the liver as an alternate energy source for the brain as well as the skeletal muscles, heart, and kidney. Low levels of ketones are always present in the blood and increase under circ*mstances of low glucose availability.
Is it healthy to go into ketosis? ›
Ketosis is a metabolic state that occurs when your body burns fat for energy instead of glucose. The keto diet has many possible benefits including potential weight loss, increased energy and treating chronic illness.
Why do I feel good in ketosis? ›
Anecdotal evidence links the initial phase of fasting or a low-carbohydrate diet with feelings of well-being and mild euphoria. These feelings have often been attributed to ketosis, the production of ketone bodies which can replace glucose as an energy source for the brain.
Do you pee a lot when in ketosis? ›
You may urinate more than normal.
Masson also said that your kidneys pump out more fluid and electrolytes when your body is in ketosis. This may affect your bladder and cause you to urinate more often, she said.
Any color on the ketone strip, from pink to purple, indicates fat burning (ketosis). Some people get a darker ketone strip color and achieve the same weight loss results as someone with a lighter color. Your “positive” color result can vary throughout the day for many reasons.
What is ketosis smell? ›
Some describe keto breath as having a metallic taste in their mouth and a smell that's sweet, fruity or similar to nail polish remover. This is caused by the chemicals your body creates during ketosis, which are released from the body by exhaling.
What food is not allowed in keto? ›
10 Foods You Can't Eat on the Keto Diet & Their Substitutes
- Grains and Starches. ...
- Sugary Foods and Sweets. ...
- High-Carb Fruits. ...
- Starchy Vegetables. ...
- Legumes and Beans. ...
- Processed Foods with Hidden Carbs. ...
- Alcohol and co*cktails. ...
- High-Carb Sauces and Condiments.
The goal of the keto diet is to achieve ketosis, or ketogenesis. Ketogenesis happens when your body uses fat instead of carbohydrates for energy. During ketogenesis, ketone bodies are formed — these are water-soluble molecules produced by the liver from fatty acids.
What happens if I eat no carbs for a month? ›
Severe carb limits can cause your body to break down fat into ketones for energy. This is called ketosis. Ketosis can cause side effects such as bad breath, headache, fatigue and weakness.
How do I know when I'm in ketosis? ›
Having ketones in the blood is probably the most definitive sign that someone is in ketosis. Doctors may also use urine and breath tests to check for ketone levels, but these are less reliable than blood samples. A special home testing kit allows people to measure their own blood ketone levels.
Is it bad to be in ketosis all the time? ›
Ketosis is likely safe for most people, especially if they follow it with a doctor's supervision. However, it can have some negative effects, especially at the start. It's also unclear how a ketogenic diet may affect the body long term ( 7 ).
Is ketosis stressful on the body? ›
Keto Can Put Stress on the Kidneys and May Give You Kidney Stones. Kidney stones are a well-noted potential side effect of the ketogenic diet. Past research observed that among children following the keto diet as a treatment for epilepsy, 13 out of 195 subjects developed kidney stones.
How long does ketosis fatigue last? ›
Keto flu symptoms may resolve themselves in a matter of days, but they can also persist for several weeks. “In most people, symptoms typically get better in 10 days; however, if headaches, fatigue, cramps or irritability last longer than that length of time, it's a good idea to see your doctor,” says Dr.
