Understanding the Ketogenic (Keto) Diet

What is a ketogenic (keto) diet? This high-fat diet helps you lose weight and increase brainpower, prompting your body to burn ketones for fuel. Learn how.

Ketosis may sound like a disease, but in fact it is a diet high in fats that helps you lose weight and increase brainpower.

Our bodies are in the state of ketosis when blood sugar and liver glycogen are no longer present and our system resorts to using ketones, a chemical stored in fat, for fuel.

If you’ve been told that ketosis is dangerous, it’s being confused with ketoacidosis, a serious condition caused by uncontrolled diabetes. Ketosis is a natural metabolic state.

“A ketogenic diet is one that derives 80 to 90 percent of its calories from fat, and the rest from carbs and proteins,” says David Perlmutter, MD, author of the best-selling “Grain Brain.” “It may sound crazy, but just remember: You’re burning those fats off, and building your brain power in the process.”

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How the keto diet works

You lose weight because your body begins to burn off fat in ketosis either because your carbohydrate intake is so low there’s no fuel from it or you haven’t eaten for a long time.

Ketosis can lead to reduced insulin levels, which causes the release of fat cells, flooding your liver with fat. Your liver then turns a large part of it into ketones.

Many parts of your body are burning ketones during ketosis, including your brain. Perlmutter explains that ketones increase glutathione (a powerful, brain-protective antioxidant) levels in your hippocampus. “Ketones facilitate the production of mitochondria,” he said, “one of the most important actors in the coordinated production that is the human body. That’s just the tip of the iceberg.”

This assumes you’re eating quality (good) fat, vegetables, and well-sourced protein, or getting all the micronutrients you need without starving yourself to lower caloric intake in one fell swoop.

When ketosis begins, your body uses ketones for energy rather than carbs. It doesn’t happen all at once, leaving the door open for some side effects.

Side effects of keto

During the adaption phase, you may experience what’s called “low-carb flu” or “keto flu.” Symptoms can include:

• Headache
• Fatigue
• Brain fog
• Increased hunger
• Poor sleep
• Nausea
• Poor physical performance

The side effects may discourage some people from continuing the diet, but the symptoms typically last only a few days.

Other side effects can include bad breath, a result of ketone metabolism. Acetone is a byproduct. You might also temporarily have leg cramps, digestive problems, and an elevated heart rate.

To minimize side effects:

• Drink plenty of water.
• Get enough salt in your diet.
• Increase your mineral intake.
• Avoid intense exercise.
• Eat fiber.

The keto diet may also cause low blood pressure, kidney stones, constipation, nutrition deficiences, and a risk of heart disease.

Is keto right for you?

If you don’t go through with a keto diet, you can try a low-carb diet instead.

Ketosis is likely an approach that doesn’t work for everyone. It will probably work for a person who avoids carbohydrates, keeps protein to moderate levels, and eats adequate levels of fat.

But being in ketosis may have benefits for people with obesity, type 2 diabetes, and children with epilepsy.

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