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Achieving ketosis is often thought of as the gold standard of successful keto dieting! But what exactly is ketosis, and how do you get into ketosis and stay there? Here’s everything you need to know about switching over to ketones for fuel and optimizing your keto diet for ketosis.
What is Ketosis and How Does it Work?
Ketosis is the metabolic state that makes a ketogenic diet so unique.
On traditional diets, your body primarily runs on energy from sugars —or more technically speaking, glucose. Carbs are your preferred source of this type of fuel since many carbs are made up of glucose and they can be quickly broken down into fast energy. But protein and fats can also supply small amounts of glucose through a process called gluconeogenesis. It is just a much slower process.
By restricting carb intake to very low levels (less than 50 grams per day), you can drastically alter the way your body finds energy. Essentially, without enough carbs to get glucose quickly, your body has to rely on an alternative source: fat!
On any diet, even high carb diets, your body uses some amount of fat for fuel—mainly at rest and in between meals. But this is typically a slow process and fat is not the main source of energy overall. In addition, fatty acids are not a desirable source of energy for your brain.
So what happens when you restrict carbs for long periods of time?
Without enough carbs for glucose, your liver produces ketones from fatty acids that can be used by your brain and can supply a quicker, more steady stream of energy to your body. This is the process of ketogenesis, resulting from a ketogenic or “keto” diet. And when ketogenesis takes over (officially switching from sugar to fatty acids as your main source of energy), you enter the metabolic state called ketosis.
What are Ketones?
While ketosis is unique to the ketogenic diet, ketone bodies are not. Ketones are produced normally during periods of starvation, fasting, or prolonged exercise. A keto diet differs in that ketone production is prolonged and increased, becoming the primary source of fuel for your muscles and brain, over anything else.
For example, ketone bodies supply less than 6% of your body's energy requirements after an overnight fast (or normal sleep patterns) but jump to 30 to 40% of your fuel after a 3‐day fast, and this increases to more than 60% during ketosis (1).
Your liver produces three types of ketones or ketone bodies:
- Acetoacetate
- Beta-hydroxybutyrate (BHB)
- Acetone
Acetoacetate is the main ketone produced by the liver during fatty acid metabolism or during restricted carbohydrate intake. It is then further converted into either BHB or acetone. Some acetoacetate is used for energy and any excess is excreted through urine—this is the ketone that urine-based keto test strips look for!
BHB is the main ketone used for fuel by your muscles and organs during ketosis, and it is the ketone body that is able to supply your brain with energy in the absence of glucose. Reaching higher BHB levels is a key desired result of ketosis.
Acetone is not as stable as the other types of ketones, so it is not the primary ketone used by the body and is only produced in small quantities. And since it is excreted when you exhale, it's acetone that's responsible for the fruity breath (keto breath) some claim to experience in ketosis.
Potential Benefits of Ketosis
There are a number of health claims out there around a ketogenic diet—including that it can cure cancer, reverse diabetes, and prevent Alzheimer's. But not all of these claims are backed by research, and most of the science surrounding keto for weight loss and a number of health conditions is still in its early stages.
But there are some possible health advantages to ketosis that are worth noting.
Ketosis Improves Insulin Sensitivity
Insulin is the hormone that regulates blood sugar control by delivering sugars to your cells as a source of usable energy and storage. The better your body responds to insulin (insulin sensitivity), the more efficiently it works. And for many with diabetes or those at risk for developing diabetes, insulin resistance (poor insulin sensitivity) can cause a host of health problems.
While more research is needed, there are a few promising studies suggesting that a keto diet may help improve insulin function more than other calorie-controlled diets (2,3,4).
In one study, participants followed a keto diet for 10 weeks and saw their HbA1C (marker for long-term blood sugar control) drop significantly, with half seeing their levels return to normal (5).
Exciting results like this are why some are claiming that low carb and keto diets may help manage diabetes.
Ketosis Might Improve Cholesterol
Contrary to what one might initially think about a high-fat diet, especially one that is typically high in animal-based fats and high sodium foods, a ketogenic diet seems to have a positive effect on blood cholesterol (6,7).
However, it is not clear whether these results are from weight loss on a keto diet or directly attributed to ketosis.
Ketosis and Weight Loss
Creating a calorie deficit is the most widely accepted approach to losing weight. However, ketosis may support weight loss efforts in a couple of different ways - primarily through increased fat burning and decreased appetite.
Ketosis is thought to allow you to become more efficient at burning fat for fuel, making fat loss easier in a calorie deficit (9). However, this is yet to be proven in well done human studies.
It also might not just be the type of food you are consuming on a keto diet that is helping to curb your appetite. In one study, Ketosis was thought to contribute to lower levels of ghrelin, a hormone responsible for increasing your hunger (10).
Although more research is needed, this hormonal response, in combination with the satiating effect of keto foods, could be an important factor in promoting more weight loss and helping you cut more calories overall on a keto diet.
How to Get Into Ketosis Fast
Here are six simple ways to promote ketosis while following a ketogenic diet.
1. Cut Carbs
The most widely recognized approach to getting into ketosis and staying there is by restricting carbohydrate intake (11). However, the number of carbs you should consume to promote ketosis can differ from one person to the next - ranging from less than 20 grams to as high as 70 to 100 grams of carbs per day for very active individuals.
Your exact carb needs for ketosis depend on the following:
- Overall calorie needs
- Fitness level
- Body composition (% body fat)
By general rule of thumb, you can assume roughly 5% or less of your calories should come from carbs, which equals around 20 grams of carbs per day for most. If your calorie needs are higher or you are extremely active, you might want to consider starting at 50 grams of carbs or higher.
Your total carb intake for ketosis is also based on net carb intake. Meaning fiber, which is also a carb, can help cancel out some of the total carbs you eat. In other words, if you eat 30 grams of carbs a day but 10 grams of it comes from fiber, your net carbs intake is still 20 grams.
2. Increase Fat Intake
Eating higher fat alone is not going to promote ketosis. However, including higher fat in your diet is a way to provide your body with a consistent source of fuel that it can use to generate ketone bodies and sustain bodily functions.
The easiest way to determine how many grams of fat you need on a keto diet is to calculate your keto macros using an online calculator or keto-friendly app.
You can also quickly estimate your daily fat needs if you know how many calories you need a day. On a typical keto diet, fat will account for 60 to 70% of your total calories.
For example, if you need 2,000 calories a day, your daily fat calories would equal roughly:
- 2,000 x (60 to 70%) = 1,200 to 1,400 calories from fat
And since there are nine calories in every gram of fat, this would equal roughly 133 to 155 grams of fat per day.
- 1,200 / 9 = 133 grams of fat
- 1,400 / 9 = 155 grams of fat
Use this simple calculator to estimate your keto macros in a few minutes:
3. Eat Medium Chain Triglycerides (MCT)
Unsaturated fats from plant-based sources have long been touted as the best sources of healthy fats and should be prioritized on any diet, including keto. But when it comes to ketosis, a certain type of saturated fat called MCT (medium chain triglycerides) may offer additional benefits.
MCTs come from plant-based saturated fats like coconut and palm oil, as well as grass-fed dairy sources like goat milk, cheese, yogurt, kefir, butter, and ghee. You can also purchase MCT oil supplements.
Unlike other fatty acids, MCTs do not require additional compounds to be digested and utilized for energy (14,15). Similar to how carbohydrates can be an immediate source of glucose, MCTs can be quickly absorbed and turned into ketones for fuel. And unlike carbs, MCTs do not affect blood sugar levels.
Their ability to form a rapid source of ketone bodies is ideal for someone on a ketogenic diet, especially during times when fast energy is needed—like during physical activity or exercise (15,16). Their rate of absorption may also aid in speeding up ketosis by promoting more ketone body formation.
4. Try Intermittent Fasting
Fasting for 24 hours for up to 3 three days is another way to get into ketosis quickly. However, this practice is not only difficult but unsustainable long-term.
Intermittent fasting or fasting for shorter windows is often discussed as an option to promote faster ketosis and strengthen the overall benefits of a keto diet (17).
It would make sense in theory that not eating for extended periods of time would help deplete glycogen stores, reduce overall carb intake, and promote more fat utilization for energy, but this all really depends on what your overall diet looks like.
Similar to most other diets, intermittent fasting is effective as another way to organize your calories to promote an overall caloric deficit. And with any fasting pattern, a deficit is only created when food choices are kept in control—not eating for fourteen hours is not a license to eat as much of whatever you want for your 10-hour window. Especially if you are trying to stay in ketosis!
But still, fasting may be the best method for some who have a hard time controlling their intake. At the end of the day, the best diet for you is one that you can stick to!
Moreover, with a focus on quality, nutritious foods, and calorie control, many may find that intermittent fasting is just what they need to manage their weight, appetite, and blood sugar levels.
5. Exercise More
Exercise can also help put you into ketosis more quickly by using up available glucose stores. Prolonged exercise or more slow-paced endurance sports (like cycling, swimming, jogging, etc.) also force you to switch to fat as a primary source of fuel, which can further support a ketotic state (18).
But not all types of exercise are sustainable without carbs. If you are participating in heavy training, high-intensity conditioning, or heavy lifting throughout the week, you might need to add some additional carbs to maintain your strength and output.
If you are an athlete or very physically active, consider adding some additional carbs (15 to 30 grams) before HIIT or heavy strength training to support your energy needs.
6. Supplement with Exogenous Ketones
Some research suggests that ketone supplements can also increase the rate at which you go into ketosis and create a ketotic state even without following a ketogenic diet (19). However, this approach is thought to be beneficial when MCTs are included.
Of course, this approach should not be a permanent substitute for a well-rounded keto diet. It is the actual act of diet-induced ketosis and carb restriction that many pro keto individuals claim is beneficial to this unique style of dieting (20,21,22).
But if you are looking to increase your level of ketones to promote ketosis quickly, a ketone supplement paired with MCT oil may be worth considering.
How Long Does it Take to Get Into Ketosis?
The rate at which you can get into ketosis depends on your activity level, body type, and overall diet.
Cutting carbs for a day isn't going to flip the switch. Your body has been running off sugars your whole life and needs time to adjust. Part of this process requires you to deplete your reserve of carb fuel (glycogen stores).
And the number of stored carbs you have can differ from one person to the next depending on how many carbs you typically eat each day and your overall muscle mass. You store these carbs in your muscles, so more muscle means more storage! Your level of physical activity also plays a role—the more you are exercising, the quicker you will run out of glycogen.
In healthy individuals who have just started the ketogenic diet, it usually takes two days to burn through glycogen. But taking all of the individual variables into account, the time frame to get into ketosis is most often quoted between 1-7 days.
How to stay in Ketosis
The easiest way to stay in ketosis is to stick to your ketogenic diet and continue to keep your carb intake low. Make sure you are tracking your daily macros using a macro tracking app, like Trifecta, and limit your keto cheat days!
Consider using a meal delivery company that does all the hard work for you. Trifecta's keto meal plan will not only help you cut carbs but it's loaded with nutrient-rich foods and healthy fats to keep your overall diet and nutrition on track.
Ready to make your keto diet a breeze?