Ketones & Low-Carb Diets

Your body produces ketones from your fat tissue when you don't get enough carbohydrates for energy. When glucose is not available, ketones are formed in your liver from fatty acids and are used to fuel the body, including the brain. The production of ketones is a normal process, but isn't usually experienced because a standard American diet contains ample carbohydrates, which make a more efficient fuel source. Very low-carb diets, however, prompt the production of ketones, putting you into a state of ketosis.

Protein and leafy greens are part of a ketogenic diet. (Image: Milkos/iStock/Getty Images)

Because a ketogenic diet can be extreme, check with your doctor before beginning one, especially if you have a history of pancreatitis, gall bladder disease, problems with fat digestion or liver function, kidney disease or gastric bypass surgery. Pregnant or breast feeding women and muscle-building athletes should most likely avoid a ketogenic diet.

How a Low-Carb Diet Leads to Ketosis

A moderately low-carb diet that contains 50 to 150 grams of carbs per day is unlikely to put you into ketosis. Most people must dip to a level of 50 grams or fewer of carbohydrates for the body to start producing ketones. The induction stage of the Atkins diet that calls for no more than 20 grams of carbs daily is an example of such a diet.

To adhere to such strict carbohydrate limitations, you avoid all breads, pasta, sugars, starchy vegetables and fruit. Soda, juices, alcohol and some condiments are also off limits. Your diet consists of moderate amounts of protein, large amounts of healthy fats and watery, fibrous vegetables.

You need ample fats to stay in ketosis and to prevent your body from going into a state of starvation, in which it uses muscle and other body tissues for fuel. Butter, cream, coconut oil, avocados and olive oil are examples of healthy fats. Nuts and nut butter may be eaten in small amounts, but do have small amounts of carbs that add up quickly when you're sticking to less than 50 grams daily.

How to Tell If You're Producing Ketones

Ketones give your breath and urine a fruity smell that some describe as being reminiscent of nail polish remover. Ketone-detecting strips for urine testing can be purchased in drug stores and will change color if you're producing ketones. After you've adapted to producing ketones, you may feel more energetic and free of cravings. A reduction in hunger is also common, which helps with weight loss.

Although the words sound similar, ketosis is different from ketoacidosis. Diabetics experience a dangerous condition called ketoacidosis when their blood sugar is not controlled; alcoholics and people suffering extreme starvation may also go into ketoacidosis. It's a completely different condition from ketosis and should be treated with medical intervention.

Side Effects of Ketone Production

Headaches, poor athletic performance and overall fatigue may plague you for the first week or two of switching to using ketones for fuel. In the initial stages of a ketogenic low-carb diet, you may feel thirsty or have dry mouth. When you significantly lower your carbohydrate intake and stores, your body produces less insulin, which prompts the kidneys to release stored water, too. Along with this release of water, you lose electrolytes -- particularly sodium -- making you feel fatigued and almost like you have the flu.

Replace electrolytes with carb-free drinks and by eating a little extra sodium. Know that these symptoms should subside in a week or two.

Benefits of Ketone Production

When your body produces ketones, it's a sign that you've become efficient at burning fat, so you lose weight more readily. As your body becomes less reliant on glucose garnered from carbohdyrates, drastic swings in your blood sugar and cravings for food disappear. A 2005 issue of the Annals of Internal Medicine published a small study showing that a low-carbohydrate, ketogenic diet decreased insulin sensitivity in diabetic participants by 75 percent.

Ketogenic diets have long been used to treat the symptoms of epilepsy in children who don't respond to medication. A low-carb diet that induces ketone production shows promise in treating heart disease, some cancers, neurological disorders and Alzheimer's.