The complete guide to ketosis

Ketosis is a metabolic state in which your body uses fat as its main energy source.

Normally, the body uses glucose, or sugar, as its primary fuel. When carb intake is very low, your liver produces lots of ketones, which are fat-like compounds that your brain and other organs can use in place of glucose.

Being in ketosis may help you feel less hungry, promote weight loss, and possibly provide other benefits.

Read on to learn all you need to know about ketosis, including tips for successfully getting into ketosis and staying there.

Three key takeaways

What is ketosis?
Ketosis is a metabolic state in which your body uses fat as its main fuel. Learn more

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What are the benefits of ketosis?
Potential benefits include appetite suppression, weight loss, and type 2 diabetes reversal. Learn more

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How can I get into ketosis?
To get into ketosis, eat fewer than 20 grams of net carbs per day, eat less often, and don’t fear fat. Learn more

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Does the brain need carbs?

There’s a long-standing yet misguided belief that carbs are necessary for proper brain function. In fact, if you ask some dietitians how many carbs you should eat, they’ll likely respond that you need a minimum of 130 grams per day to ensure that your brain has a steady supply of glucose.

However, this isn’t the case. In fact, your brain will remain healthy and functional even if you don’t eat any carbs at all.

Although it’s true that your brain has high energy demands and requires some glucose, ketones can provide about 70% of the brain’s needed fuel. The liver provides the remainder of needed energy in the form of glucose, which is made by gluconeogenesis (literally “making new glucose”).

This system allowed our hunter-gatherer ancestors to go for long periods without eating because they had access to a fuel source at all times: stored body fat.

Being in ketosis doesn’t have any adverse effects on brain function. On the contrary, many people have reported that that they feel sharper mentally when they’re in ketosis.

Food for thought: Does the brain need carbs?

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2. Benefits of ketosis

In addition to providing a sustainable energy source, ketones – and in particular BHB – may help reduce inflammation and oxidative stress, which are believed to play a role in the development of many chronic diseases.

Indeed, there are several established benefits and potential benefits of being in nutritional ketosis.

Established benefits:

• Appetite regulation: One of the first things people often notice when they’re in ketosis is that they aren’t hungry as often. In fact, research has shown that being in ketosis suppresses appetite.
  Studies also show a decrease in ghrelin, the so-called “hunger hormone.”
• Weight loss: Many people naturally eat less when they restrict carbs and are allowed as much fat and protein as they need to feel full. Because ketogenic diets suppress appetite, decrease insulin levels, and increase fat burning, it isn’t surprising that they’ve been shown to either outperform or be equivalent to other diets intended for weight loss.
• Reversal of diabetes and prediabetes:
  In people with type 2 diabetes or prediabetes, being in ketosis can help normalize blood sugar and improve insulin sensitivity, potentially leading to the discontinuation of diabetes medication.
• Potentially enhanced athletic performance: Ketosis may provide an extremely long-lasting fuel supply during sustained exercise in both high-level and recreational athletes.
• Seizure management: Maintaining ketosis with the classical ketogenic diet or less stringent modified Atkins diet (MAD) has been proven effective for controlling epilepsy in both children and adults who don’t respond to anti-seizure medication.

There is also exciting early research suggesting that ketosis may be beneficial for many other conditions, such as reducing the frequency and severity of migraine headaches, reversing PCOS, perhaps enhancing conventional brain cancer therapies, possibly slowing down the progression of Alzheimer’s disease, along with potentially helping people live longer, healthier lives. Although higher quality research is needed to confirm these effects, much of the early research is very encouraging.

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3. Nutritional ketosis vs. ketoacidosis

Nutritional ketosis and diabetic ketoacidosis are entirely different conditions. While nutritional ketosis is safe and beneficial for health, ketoacidosis is a medical emergency.

Unfortunately, many healthcare professionals don’t really understand the distinction between the two.

Ketoacidosis occurs mainly in people with type 1 diabetes if they aren’t getting enough insulin to meet their needs. In diabetic ketoacidosis (DKA), blood sugar and ketones rise to dangerous levels, which disrupts the blood’s delicate acid-base balance.

In nutritional ketosis, BHB levels typically remain below 5 mmol/L. However, people in diabetic ketoacidosis often have BHB levels of 10 mmol/L or above, which is directly related to their inability to produce insulin.

This graph shows the vast difference in the amount of ketones in the blood between ketosis and ketoacidosis:

Other people who can potentially go into ketoacidosis are those with type 2 diabetes who take medications known as SGLT-2 inhibitors, such as empagliflozin, canagliflozin, dapagliflozin, and ertugliflozin.

Also, in rare cases, women who don’t have diabetes can develop ketoacidosis while breastfeeding.

However, for most people capable of producing insulin, it’s nearly impossible to go into ketoacidosis.

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