Cutting Carbs, Trying a Short Fast, and Other Ways to Get Into Ketosis
- November 16, 2021
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Ketosis is a normal metabolic process that provides several health benefits.
During nutritional ketosis, your body converts fat into compounds known as ketones and begins using them as its main source of energy. Ketones are also known as ketone bodies.
That said, achieving a state of ketosis can take some work and planning. It’s not just as simple as cutting carbs.
Here are 7 effective tips to get into ketosis.
Eating a very low carb diet is by far the most important factor in achieving ketosis.
Your cells normally use glucose, or sugar, as their main source of fuel. However, most of your cells can also use other fuel sources, including fatty acids and ketones.
Your body stores glucose, in the form of glycogen, in your liver and muscles.
When your carb intake is very low, glycogen stores are reduced and levels of the hormone insulin decline. This allows fatty acids to be released from fat stores in your body.
The degree of carb restriction needed to induce ketosis varies by individual and can be affected by various factors, such as the types of exercise you do.
Some people need to limit their net carb intake to 20 grams per day, while others can achieve ketosis while eating twice this amount or more.
For this reason, the induction phase of the Atkins diet requires that carbs be restricted to 20 or fewer grams per day for 2 weeks to guarantee that ketosis is achieved.
After this point, small amounts of carbs can be added back to your diet very gradually, as long as ketosis is maintained.
Each individual will potentially have a different carb intake limit to achieve and maintain ketosis, depending on the total number of calories they eat and their daily activity levels. Generally, eating 5–10% of total calories from carbs will produce ketosis.
In one study, adults with type 2 diabetes were allowed 20–50 grams of digestible carbs per day, depending on the number of grams that allowed them to maintain blood ketone levels within a certain target range (7).
These carb and ketone ranges are advised for people who want to get into ketosis to promote weight loss, control their blood sugar levels, or reduce their heart disease risk factors.
However, anyone using the diet for therapeutic purposes should only do so under the supervision of a medical professional.
Limiting your carb intake to 20–50 net grams per day lowers your blood sugar and insulin levels, leading to the release of stored fatty acids that your liver converts into ketones.
Eating coconut oil can help you achieve ketosis.
It contains fats called medium-chain triglycerides (MCTs).
Unlike most fats, MCTs are rapidly absorbed and taken directly to the liver, where they can be used immediately for energy or converted into ketones.
In fact, it has been suggested that consuming coconut oil may be one of the best ways to increase ketone levels in people with Alzheimer’s disease and other nervous system disorders (10).
Although coconut oil contains four types of MCTs, around 50% of its fat comes from the kind known as lauric acid (11).
Some research suggests that fat sources with a higher percentage of lauric acid may produce a more sustained level of ketosis. This is because it’s metabolized more gradually than other MCTs (11, 12).
MCTs have been used to induce ketosis in children who have epilepsy. In a high MCT diet, ketosis occurs without restricting carbs as drastically as the classic ketogenic diet.
In fact, several studies have found that a high MCT diet containing around 20% of calories from carbs produces effects similar to those of the classic ketogenic diet. The classic ketogenic provides fewer than 5% of calories from carbs (8, 13, 14, 15).
When adding coconut oil to your diet, it’s a good idea to do so slowly to minimize digestive side effects like stomach cramping or diarrhea.
Consuming coconut oil provides your body with medium-chain triglycerides (MCTs), which are quickly absorbed and converted into ketones by your liver.
In addition, being more active can help you get into ketosis.
When you exercise, you deplete your body’s glycogen stores. These are normally replenished when you eat carbs, which are broken down into glucose. The glucose that isn’t needed immediately is stored as glycogen.
However, if carb intake is minimized, glycogen stores remain low. In response, your liver increases its production of ketones, which can be used as an alternative fuel source for your muscles (18).
In a small 2009 study, 9 postmenopausal women exercised either before or after a meal. Their blood ketone levels were 137–314% higher when they exercised before a meal than when they exercised after a meal (20).
Keep in mind that although exercise increases ketone production, it may take 1–4 weeks for your body to adapt to using ketones and fatty acids as primary fuels. During this time, physical performance may be reduced temporarily (21).
Engaging in physical activity can increase ketone levels during carb restriction. This effect may be enhanced by working out in a fasted state.
Consuming plenty of healthy fats can boost your ketone levels and help you reach ketosis.
Indeed, a very low carb ketogenic diet not only minimizes carbs but also calls for a high fat intake.
However, extremely high fat intake doesn’t necessarily translate into higher ketone levels.
A 3-week study including 11 healthy people compared the effects of fasting on breath ketone levels. Overall, ketone levels were found to be similar in people consuming 79% of calories from fat and people consuming 90% of calories from fat (26).
Because fat comprises such a large percentage of a ketogenic diet, it’s important to choose high quality fat sources.
Healthy fats include fatty fish, olive oil, and avocado oil. In addition, many healthy and high fat foods are also very low in carbs.
However, if weight loss is your goal, it’s important to make sure you’re not consuming too many calories in total, as this can cause your weight loss to stall.
Consuming at least 60% of calories from fat will help boost your ketone levels. Choose a variety of healthy fats from both animal and plant sources.
Another way to get into ketosis is to go without eating for several hours.
In fact, many people go into mild ketosis between dinner and breakfast.
Moreover, “fat fasting” is another ketone-boosting approach that mimics the effects of fasting.
It involves consuming approximately 700–1,100 calories per day, around 80% of which come from fat. This combination of low calorie intake and very high fat intake may help you achieve ketosis quickly (26, 31).
Because a fat fast is inadequate in protein and most vitamins and minerals, it should be followed for a maximum of 3–5 days. In fact, it may be difficult to adhere to for more than a couple of days.
Fasting, intermittent fasting, and a “fat fast” can all help you get into ketosis relatively quickly.
Achieving ketosis requires a protein intake that’s adequate but not excessive.
The classic ketogenic diet used in people with epilepsy restricts both carbs and protein to maximize ketone levels.
However, for most people, drastically cutting their protein intake to increase ketone production isn’t a healthy practice.
First, it’s important to consume enough protein to supply the liver with amino acids that can be used for gluconeogenesis, or making glucose (34).
In this process, your liver provides glucose for the few cells and organs in your body that can’t use ketones as fuel, such as your red blood cells and portions of your kidneys and brain (35).
Second, protein intake should be high enough to maintain muscle mass when carb intake is low, especially during weight loss.
Although losing weight typically results in the loss of both muscle and fat, consuming sufficient amounts of protein on a very low carb ketogenic diet can help preserve muscle mass (36).
Several studies have shown that the preservation of muscle mass and physical performance is maximized when protein intake is in the range of 0.55–0.77 grams per pound (1.2–1.7 grams per kilogram) of lean mass (21).
A daily protein intake of 0.45–0.68 grams per pound (1–1.5 grams per kilogram) will help you maintain lean mass while losing weight (23).
In one study in 17 men with obesity, following a ketogenic diet providing 30% of calories from protein for 4 weeks led to blood ketone levels of 1.52 mmol/L, on average. This is well within the 0.5–3 mmol/L range of nutritional ketosis (37).
To calculate your protein needs on a ketogenic diet, multiply your ideal body weight in pounds by 0.55–0.77 (1.2–1.7 in kilograms). For example, if your ideal body weight is 130 pounds (59 kg), your protein intake should be 71–100 grams.
Consuming too little protein can lead to muscle mass loss, whereas excessive protein intake may suppress ketone production.
Like many things in nutrition, achieving and maintaining a state of ketosis is highly individualized.
Therefore, it can be helpful to test your ketone levels to ensure you’re achieving your goals.
The three types of ketones — acetone, acetoacetate, and beta-hydroxybutyrate — can be measured in your breath, urine, or blood. Using one or more of these methods to test ketones can help you determine whether you need to make any adjustments to get into ketosis.
Acetone and the breath test
The Ketonix meter measures acetone in your breath. After breathing into the meter, a color flashes to indicate whether you’re in ketosis and how high your levels are.
Acetoacetate and the urine tests
The ketone measured in urine is acetoacetate. Ketone urine strips are dipped into urine and turn various shades of pink or purple depending on the level of ketones present. A darker color reflects higher ketone levels.
Ketone urine strips are easy to use and fairly inexpensive. Although their accuracy in long-term use has been questioned, they should initially confirm that you’re in ketosis.
A 2016 study found that urinary ketones tend to be highest in the early morning and after dinner on a ketogenic diet (40).
Beta-hydroxybutyrate and the blood test
Lastly, ketones can also be measured with a blood ketone meter. Similar to the way a glucose meter works, a small drop of blood is placed on a strip that’s inserted into the meter.
The disadvantage of measuring blood ketones is that the strips are very expensive.
Using breath, urine, or blood tests to measure your ketone levels can help ensure that you’re achieving and maintaining ketosis.
When you get into ketosis, your body begins to use ketones for fuel.
For people who’ve adopted a ketogenic diet as a means to lose weight, getting into ketosis is an important step toward that goal. Other benefits of ketosis include seizure reduction in people with epilepsy.
Cutting your carbs is the best way to achieve ketosis. Other actions, such as consuming coconut oil or exercising in a fasted state, may also help.
Quick and easy methods, like using special urine strips, can let you know whether you’re maintaining ketosis or your diet needs some adjustments.