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.
Is ketosis safe and does it have side effects? ›
The keto diet could cause low blood pressure, kidney stones, constipation, nutrient deficiencies and an increased risk of heart disease. Strict diets like keto could also cause social isolation or disordered eating. Keto is not safe for those with any conditions involving their pancreas, liver, thyroid or gallbladder.
How long does it take for your body to go into ketosis? ›
For healthy people who don't have diabetes and aren't pregnant, ketosis usually kicks in after 3 or 4 days of eating fewer than 50 grams of carbohydrates per day. That's about three slices of bread, a cup of low-fat fruit yogurt, or two small bananas. You can start ketosis by fasting, too.
Does your pee change color in ketosis? ›
To test your ketone levels, you can use test trips that you dip in your urine. They change color based on the presence of the ketones. The darker the strip, the higher the level of ketones. This method isn't as accurate as a blood test, but it is simple, cheap, and easy enough for everyday use.
What happens to the liver during ketosis? ›
Your liver breaks down fat and converts it to energy and cholesterol. A high-fat diet like the keto diet can cause fat to build up in your liver and lead to fatty liver disease. Animal studies suggest the keto diet can cause non-alcoholic fatty liver disease, or NAFLD, and raise liver enzyme levels.
Is ketosis hard on your body? ›
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 ).
What organ does ketosis affect? ›
When your body doesn't have enough glucose to power these cells, levels of the hormone insulin decrease, causing fatty acids to be released from body fat stores in large amounts ( 1 , 4 ). Many of these fatty acids are transported to the liver, where they're oxidized and turned into ketones, also called ketone bodies.
Is keto hard on the kidneys? ›
The ketogenic diet is becoming more popular as a weight loss regimen; however, the evidence has failed to show clinically significant benefits over comparator diets. Even worse, it may cause hyperlipidemia, vitamin and mineral deficiencies, fatigue, and kidney damage, among other complications (Figure 1) [6].
Is keto good for seniors? ›
People over 50 may have success on the keto diet, because it has the potential to promote weight loss, control blood sugar, and possibly protect against heart disease. But this eating plan does have risks, and you should always check with your doctor or a licensed nutritionist before you start any new diet.
What foods put your body in ketosis? ›
Foods you can eat on the keto diet include fish and seafood, meat and poultry, non-starchy vegetables like bell peppers, broccoli, and zucchini, avocados, berries, nuts and seeds, eggs, high-fat dairy products, olive oil and other oils, and high-cocoa chocolate.
If a person follows the 75% fat /20% carb/5% fat keto diet, average results may look like this: Weeks 1–2: rapid weight reduction phase due to water loss – up to ten pounds. Weeks 2–4: standard weight reduction – between one and two pounds per week. After the first month – slow weight loss – around one pound per week.
Does ketosis change your poop? ›
If you've been following the ketogenic (“keto”) diet, your excitement about the eating plan might be tempered by a common — but not often talked about — side effect: constipation or diarrhea.
Can you smell ketosis in urine? ›
When a person eats a lot of protein instead of carbohydrates, their body uses protein and stored fat for energy instead of using carbohydrates as it would usually do. As a result, the ketone level in the blood will rise. When these ketones leave the body in the urine, the urine may smell sweet or similar to popcorn.
Is it good for your body to be in ketosis? ›
Ketosis can have a few significant health benefits: Promotes weight loss: In the short term, ketosis can help you lose weight by reducing your body's stores of glycogen, the storage form of glucose in muscles and liver, and water. In the long term, it can suppress your appetite and cause you to eat less.
Is it healthy to go into ketosis? ›
Possible benefits of ketosis include weight loss, improved blood sugar management, and reduced seizures in children with epilepsy. However, following a strict ketogenic diet to induce ketosis can be difficult and lead to unwanted short-term side effects like headaches, stomach upset, dehydration, and bad breath.
How long can you stay in ketosis safely? ›
Following the keto diet for an extended period of time can be difficult, and even some of its top proponents warn against sticking to its strict guidelines. This includes cutting back carbohydrates to 50 grams a day or less, for at least two to three weeks up to six to 12 months, per the National Library of Medicine.
Does your body get better at ketosis? ›
Over time, the body will acclimate to use ketone bodies as a primary fuel to achieve keto-adaptation. Keto-adaptation may provide a consistent and fast energy supply, thus improving exercise performance and capacity.
Is it good to be in ketosis all the time? ›
But for weight loss and general well-being in healthy adults, there's no need to be in ketosis all the time. People who typically do keto might benefit from short periods out of ketosis, and people who aren't fully on the keto train might benefit from switching to a fat-burning metabolism every now and again.
