The ketogenic diet, lovingly referred to as "keto" by most who follow it, is a high-fat, very low-carbohydrate dietary plan whose goal is to change your metabolism. The main objective is to kick-start ketosis, which is a metabolic state where your body burns fat for energy (instead of carbohydrates). While many people turn to the ketogenic diet to lose extra pounds, the benefits of ketosis reach beyond weight loss.
In addition to helping you lose weight, ketosis may also increase your energy, improve your concentration, decrease inflammation and improve your blood sugar markers, reducing your risk of developing diabetes. A study published in the journal Seizure in 2014 also linked ketosis to reduced severity and frequency of seizures in those with epilepsy and a slower progression of Alzheimer's disease.
Using Carbohydrates for Energy
Your body likes to use carbohydrates for energy above all else. When you eat foods that contain carbohydrates, your body breaks them down into a simple sugar called glucose. Glucose enters your blood, which signals the release of a hormone called insulin from your pancreas.
When insulin gets into your blood, it attaches to glucose and does two things with it:
- Some glucose is carried straight to your cells and burned off immediately for energy.
- The rest is converted to glycogen, which is stored in your liver and your muscles for your body to use as energy later.
Read more: How Does Glucose Provide Energy?
Getting Into Ketosis
If you're providing your body with a steady supply of carbohydrates, this process stays on repeat. As a result, any dietary fat that you eat gets stored in your body. On a ketogenic diet, you limit your carbohydrate intake enough to interrupt this process.
When your body doesn't have access to carbohydrates, it starts burning fat for energy instead. To effectively burn fat for energy, your liver breaks it down into fatty acids, which are then converted into substances called ketones. When you have ketones in your blood, you're in ketosis.
Balancing Your Macronutrients
The exact number of each macronutrient that you need to get into ketosis varies between individuals, but in general the macronutrient ratio for a ketogenic diet looks something like this:
- 5 to 10 percent of calories from carbohydrates
- 60 to 75 percent of calories from fat
- 15 to 30 percent of calories from protein
You'll probably have to experiment with these ratios until you've hit your sweet spot, but for most people, this is a good place to start.
Benefits of Ketosis
The benefits of ketosis are far-reaching. Many people are drawn to the ketogenic diet for weight loss, but that's only the tip of the iceberg. Other benefits include:
- Increased energy
- Decreased body fat/increased muscle mass
- Decreased inflammation
- Decreased appetite/improved satiety
- Improved concentration
- Improved sleep
- Better blood sugar regulation (decreased blood sugar/improved insulin sensitivity)
- Reduced blood pressure and blood cholesterol
- Improved exercise performance
- Slowed disease progression of neurological diseases, like Parkinson's disease and Alzheimer's Disease
- Reduced severity and frequency of seizures in people with epilepsy
Another benefit of ketosis is an unlimited supply of energy for your body. Your body can only store a certain amount of carbohydrates in your liver and your muscles, but there's no limit to the amount of fat it can store. According to a report published in Nutrition Reviews in 2018, your body can store a total of 600 grams of glycogen, which is divided between the liver and your muscles. On the other hand, it can store as much fat as you give it.
In other words, if your body is burning carbohydrates for energy, it will eventually reach a point where it doesn't have any stored energy left; but if your body is burning ketones, you'll have an unlimited energy reserve.
Constipation on a Ketogenic Diet
One of the most commonly reported disadvantages of a ketogenic diet is constipation. The diet requires you to eliminate most sources of carbohydrates, which also happen to be some of the foods with the highest amount of fiber. As a result, digestion can slow down and leave you feeling uncomfortable, especially in the beginning stages as your body adjusts.
You can combat constipation by including plenty of fiber-rich, low-carbohydrate foods, like chia seeds, leafy greens, broccoli and cauliflower, in your diet. You may also opt to add a fiber supplement to your daily routine.
Other Disadvantages of Ketogenic Diet
Another disadvantage of ketogenic diets is the strict nature. Getting into (and staying in) ketosis requires that you restrict carbohydrates indefinitely. That means that one day of going over your recommend carbohydrate needs can kick you out of ketosis.
You'll need to eliminate sweets, grains and alcohol for as long as you intend to remain in ketosis. As a result, many people find sticking with the diet long-term difficult. "Cheat days" or "cheat meals" are difficult to include in the plan as one high-carbohydrate meal can turn your body back to burning carbohydrates for energy, which can take days (and even up to a week) to reverse.
Nutrient deficiencies and dehydration are also possible on the ketogenic diet, especially if you're unsure of how to create a balanced diet while also eliminating certain food groups. If your diet doesn't contain a variety of foods, you may be taking in insufficient amounts of certain vitamins and minerals, like magnesium and other electrolytes.
Ketosis vs. Ketoacidosis
Ketosis is different than ketoacidosis, a potentially life-threatening complication of diabetes. Ketoacidosis develops when the body can't produce (or is not getting) enough insulin and, instead, starts breaking fatty acids down into ketones at a rapid speed. Because there's not enough insulin in the blood, both glucose and ketone levels get too high.
Symptoms of ketoacidosis include:
- Excessive thirst
- Excessive urination
- Flushed skin
- Stomach pain
- Loss of consciousness
Ketoacidosis is considered a medical emergency. If you're experiencing any these symptoms, seek medical attention. If you're diabetic, speak with your medical care provider before attempting a ketogenic diet.
- European Journal of Clinical Nutrition: Beyond Weight Loss: A Review of the Therapeutic Uses of Very-Low-Carbohydrate (Ketogenic) Diets
- Seizure: Ketogenic Diet in Adolescents and Adults With Epilepsy
- Obesity Review: Do Ketogenic Diets Really Suppress Appetite? A Systematic Review and Meta-Analysis
- Journal of Postgraduate Medicine: Ketogenic Diet in Endocrine Disorders: Current Perspectives
- European Journal of Clinical Investigation: Ketogenic Diets: From Cancer to Mitochondrial Diseases and Beyond
- Nutrition Reviews: Fundamentals of Glycogen Metabolism for Coaches and Athletes
- Kiss My Keto: Keto Macros: A Guide to Understanding Nutrient Ratios
- Medical News Today: Ketosis: What Is Ketosis?
- Amazon.com: Keto Advantage Reviews
- Medical News Today: Ketosis vs Ketoacidosis: Differences, Symptoms and Causes
- Medical News Today: What Is Ketosis? What Causes Ketosis?