Ketosis: How Quickly Does It Work And How Fast Ketosis Happens?

Ketosis is a metabolic state in which the body uses ketones, which are derived from fat, as its main source of energy instead of carbohydrates. This state can be reached in as little as 24 hours, but it usually takes between two and seven days. The time it takes to reach ketosis depends on several factors, including metabolism, physical activity levels, age, body composition, sleep habits, and stress levels. To reach ketosis, one must reduce their carbohydrate intake to 50 grams or fewer per day and increase their intake of healthy fats. Intermittent fasting and high-intensity exercise can also help accelerate the process.

Reduce carbohydrate intake

Reducing your carbohydrate intake is the most important factor in entering ketosis. Ketosis is a metabolic state in which the body uses fat, instead of glucose, for fuel. Typically, the body uses glucose, or sugar, as its main energy source. However, when there is a lack of glucose, the body burns fat for this purpose instead.

To reach ketosis, you should reduce your carb consumption to 50 grams or less per day. However, the exact limit can vary from person to person, and some people can begin producing ketones while still eating 70-90 grams of carbohydrates per day. Generally, the ketogenic diet drops carb intake to around 50 grams per day.

The time it takes to achieve ketosis depends on the individual. If you've lowered your carbs to around 20-50 grams daily, it usually takes 2-4 days to enter ketosis. For some people, it might take a week or longer.

Those who are healthier and more metabolically adapted might achieve ketosis faster than those who aren't. If you usually eat a high-carb diet, it might take you longer to reach ketosis than those who generally consume a low-to-moderate amount of carbohydrates. This is because your body has to deplete its glycogen stores before entering ketosis.

You might experience some symptoms, known as the "keto flu", as you transition from burning carbs to burning fat. These symptoms might include fatigue, nausea, and increased thirst.

• Embrace fasting: If you're serious about reaching ketosis, consider embracing a period of fasting. This will cause your body to burn through its stored glucose and force it to create a new kind of fuel - ketone bodies. However, fasting alone might not be enough to reach ketosis, and you might need to add another element such as exercise.
• Increase your physical activity: Exercise helps reduce the body's stores of glycogen, a form of glucose. Usually, eating carbs restores glycogen levels. But on a low-carb diet, you're not sufficiently replenishing these stores, which encourages the body to turn to fat as a source of fuel instead. Keep in mind that it can take some time for your body to adjust to using fat as fuel, and you may experience fatigue during this transition period.
• Manage your minerals: When you deplete your glucose stores over a short period, you lose a lot of water, along with water-soluble minerals like sodium, potassium, and magnesium. These electrolytes are essential for health and wellness, so it's important to manage your mineral intake. Consider taking a mineral supplement, especially if you're combining a low-carb diet with fasting and exercise.
• Monitor your ketone levels: Testing your ketone levels can help you track your progress and make adjustments to your diet. You can test your ketone levels through your urine, blood, or breath.
• Try intermittent fasting: Intermittent fasting can help you reach a state of ketosis by depleting your body's stored glycogen and increasing the production of ketone bodies. You can start with a 12-hour fast and combine it with exercise for the best results. Remember to break your fast with low-carb foods such as bone broth, leafy greens, eggs, and meat.
• Avoid supplements: Supplements like keto pills claim to kickstart ketosis, but preliminary studies suggest otherwise.

Increase physical activity

If you want to reach ketosis in 24 hours, you need to exercise. The more energy you use, the more fuel your body needs. Exercise helps to reduce the body's stores of glycogen, a form of glucose. Typically, eating carbs restores glycogen levels, but if you're on a low-carb diet, your body will turn to fat as a source of fuel instead.

If you want to deplete your glucose stores quickly, you should try high-intensity cardio or resistance training. Activities like running, kickboxing, biking, or high-intensity interval training (HIIT) will allow you to rapidly deplete glucose stores and prime your body to start making ketones. As a general rule, you should work out in the morning so that you can burn through much of your glucose stores early on in your fast.

However, it's important to note that exercise can mess with the accuracy of your blood glucose and ketone readings. This is because the hormonal response to exercise causes stored glucose to be released from your liver and skeletal muscle, which temporarily raises the glucose in your blood. So, get your workout out of the way early, and you'll have more energy to train and ensure a more accurate ketone and blood glucose reading at the end of your 24-hour keto adventure.

By increasing your physical activity, you can speed up the process of reaching ketosis. However, it's important to be aware that it may take 1-4 weeks for your body to adapt to using ketones and fatty acids as primary fuel sources, and your physical performance may be temporarily reduced during this adjustment period.

Fast for short periods

Fasting for short periods is one way to reach ketosis faster. Intermittent fasting (IF) can help a person reach a state of ketosis. In some controlled cases, a doctor may recommend fasting periods of 24–48 hours, but most people do not need to fast this long to reach ketosis. Studies involving children with epilepsy show that fasting for two or three days triggers ketosis quickly.

If you're serious about reaching ketosis in 24 hours, then forget about food. You need to shut the fridge, close the cabinets, and embrace the glucose-burning power of fasting! If you maintain a low-carb diet leading up to your fast, you’ll have an easier time. You won’t be as susceptible to the mental and physical crash that can accompany fasting. And thus, your mood and energy shouldn’t suffer.

You can start with a 12-hour fast, the shortest possible fasting duration, and combine it with exercise for the best results. Make sure to break your fast with low-carb foods, such as bone broth, leafy greens, eggs, and meat.

Fasting alone won’t bring you to the promised land of nutritional ketosis. To reach ketosis in 24 hours, you need to add another element to your game... exercise! There are all sorts of reasons why you should exercise regularly. But if you want to achieve ketosis in 24 hours, you have just one goal with your exercise: burn glucose. You can skip the heavy weights and slow movements. What we need is high-intensity cardio or resistance training. Engaging in activities like running, kickboxing, biking, or high-intensity interval training (HIIT) will allow you to rapidly deplete glucose stores and prime your body to start making ketones. As a general rule, you’ll want to work out in the morning. That way, you can burn through much of your glucose stores early on in your fast.

Increase healthy fat intake

To enter ketosis, it is recommended that 70-80% of your daily calories come from fat. This is because ketosis is a metabolic state in which your body uses fat, instead of glucose, for fuel.

Healthy Fats to Eat on the Keto Diet

• Avocados and avocado oil
• Nuts and seeds (e.g. almonds, hazelnuts, pistachios, pecans, pumpkin seeds, sunflower seeds, and sesame seeds)
• Nut and seed butters (e.g. sunflower butter, almond butter)
• Flax seeds
• Hemp hearts
• Chia seeds
• Olives and cold-pressed olive oil
• Coconuts and unrefined coconut oil
• Cacao nibs
• Full-fat Greek yogurt
• Fatty fish (e.g. salmon, tuna, anchovies, sardines, and mackerel)
• Eggs
• Butter
• Cheese

Tips for Increasing Your Healthy Fat Intake

• Enjoy creamy soups and sauces
• Use multiple fat sources at each mealtime
• Dunk veggies in high-fat dips
• Roast vegetables in oil
• Sprinkle nuts and seeds over meals
• Whip up a full-fat dairy smoothie
• Add shredded coconut to snacks and sweets
• Load up on avocado

Test ketone levels

Testing your ketone levels is a helpful way to know whether you're starting ketosis or staying in ketosis. The three types of ketones — acetone, acetoacetate, and beta-hydroxybutyrate — can be measured in your breath, urine, and blood, respectively.

Breath testing

Breath testing measures ketone acetone, which is exhaled through the lungs. It is non-invasive and convenient and uses a portable breath-acetone meter. Ketosis can produce breath acetone concentrations of 2–40 ppm.

Urine testing

Urine testing measures ketone acetoacetate, which is excreted through the urine. Ketone test strips are dipped into the urine and change to various shades of pink or purple depending on the level of ketones present. The darker the colour, the deeper the ketosis. Urine strips are fairly inexpensive and easy to use, but their accuracy in long-term use has been questioned. A 2016 study found that, in people on a ketogenic diet, urinary ketones tend to be highest in the early morning and after dinner.

Blood testing

Blood testing is the most accurate way to check for ketosis. It measures the amount of beta-hydroxybutyrate in your blood. It involves pricking your finger and taking a small blood sample, which is then analysed by a small blood ketone meter. The optimal range for nutritional ketosis is 0.5–3.0 mmol/L. The disadvantage of measuring blood ketones is that the strips are very expensive.

Frequently asked questions