Everything You Need to Know About Ketosis

Ketosis is a metabolic state in which your body uses fat rather than sugar for energy. Your body shifts into ketosis when your blood sugar is low, and the glycogen in your muscles has been depleted. Typically, this happens when you eat a low carb diet or fast from food altogether for a prolonged period. Ketosis is usually heralded as a fast and effective way to lose body fat. Research suggests that ketosis may positively affect health in other ways, as well.

How Does Ketosis Work?

Normally, your body is powered by sugar from carbohydrates, a macronutrient. However, if you drastically limit your intake of carbs, your body will tap into its sugar reserves, called glycogen. Once those are used up, a process that takes about three days, your liver begins to metabolize fat. This process is known as ketogenesis, and it produces ketones. Ketones are byproducts of fat metabolism that your body can use as an alternative form of energy.^[1] One technical side note — some components of your body require a very small amount of sugar, but your body can produce that small amount of sugar by itself in a process called gluconeogenesis.^[2]

The Ketogenic Diet

For your body to shift into ketosis, you must consume almost no carbohydrates. There are a couple of ways to limit your carb intake. One is through various types of fasting; another is by following a ketogenic diet.

The ketogenic diet is high in fat (70 to 80 percent of your daily calorie intake), low in protein (15 to 20 percent), and very low in carbohydrates (5 to 10 percent with no more than 20 to 30 grams of carbs per day).^[3] There are different variations of the ketogenic diet, but, in general, it consists of low carb vegetables like leafy greens (not starchy vegetables like potatoes and corn) and healthy sources of fat and protein like nuts, seeds, avocados, and olive oil. Depending on preference and dietary restrictions, some people consume eggs, meat, and fish.

How to Tell If You’re in Ketosis

A few telltale signs that your body is in ketosis include a rebound in energy and a lack of appetite. If you need a more definite answer, there are a couple of ways to determine if your body is in ketosis and to what degree. Urine test strips are the most common. They’re widely available and are color-coded to measure the presence of ketones in urine. Tests have also been developed to detect ketosis through exhaled breath.^[4]

Health Benefits of Ketosis & the Ketogenic Diet

There are many health benefits of following a ketogenic diet. Putting your body into a state of ketosis may help with neurological disorders and sensory disturbances, abnormal cell development, and even recovery from spinal cord injury.^{[5, 6, 7]} Most often, though, ketosis is praised for its beneficial effects on weight loss, blood sugar, and overall well-being.

Ketosis & Weight Loss

Because the ketogenic diet causes the body to burn stored body fat, it is effective for promoting weight loss.^[8] A 2008 study that was published in the American Journal of Clinical Nutrition found that overweight men who followed a ketogenic diet for a month lost, on average, 12 pounds.^[9] Many people in ketosis develop healthier cholesterol levels, too.^[10]

Ketosis & Blood Sugar

The ketogenic diet restricts the consumption of sugar, and it’s a helpful way to manage blood sugar levels.^[11] In fact, many of the benefits of ketosis and the ketogenic diet are directly or indirectly related to reduced sugar intake.

Persons with type 1 diabetes may be susceptible to ketoacidosis, a potentially serious condition in which the acidity of the blood increases. They should not follow a ketogenic diet or seek ketosis without approval and observation from their trusted, natural healthcare provider.

Ketosis & Healthy Aging

The ketogenic diet can help slow and soften the effects of aging by promoting longevity and strength.^[12] Some research even suggests that it improves risk factors for some age-related health conditions.^[13]

Ketosis & Brain Health

According to researchers at the Mayo Clinic, a low carb diet supports normal cognitive function.^[14] Studies also suggest that the ketogenic diet may be helpful for neurodegenerative diseases.^[15] This is because ketosis protects neurons from oxidative damage in the neocortex, the wrinkled, folded outer layer of the brain.^[16] Damage to this area is a characteristic of neurodegenerative diseases.^[1]

Ketosis & the Immune System

According to researchers at Yale School of Medicine, ketones support normal immune system function.^[17] In one study, researchers found that hypersensitivity to allergens was significantly reduced when ketone levels were elevated.^[1] Additionally, the diet stimulates the body’s immune cell recycling process to clear out old, worn-out cells and make room for fresh, new, robust immune cells.^[18]

Are There Side Effects of Ketosis?

It’s important to note that as ketones are produced, the acidity of the blood also increases. For most people, this isn’t an issue. For some people, like those with type 1 diabetes who don’t produce insulin, it can lead to ketoacidosis, a serious condition that can prove fatal. Ketoacidosis can also occur in people with type 2 diabetes, although it is much less common.

Ketosis is an individual experience that can be difficult to begin, but the rewards are tremendous. The first two or three days are regarded as the hardest since you’re not eating sugar, but your body hasn’t yet entered ketosis. As a result, most people report feeling hungry, tired, irritable, and slow.^[19] Once ketosis kicks in, and they start burning fat, their physical energy and mental clarity return. It can be tough, but the juice is worth the squeeze.

If you’re interested in putting your body in ketosis but aren’t sure where to start, check out my ketogenic fast. I’ve received a lot of positive feedback from people who’ve tried it.