What is a ketogenic diet?
A ketogenic diet is a diet that contains high fat containing foods and very less carbohydrate containing foods. However, it includes sufficient protein food sources to meet the protein requirements of the body. The ketogenic diet was first introduced in 1924 by Dr Russell Wilder to treat epileptic patients at the Mayo clinic (1).
What does ketogenic diet do to your body?
Carbohydrate is the prime energy source of the body. When consumed, it is converted into glucose, which fuels the various functions of the body. Under conditions of carbohydrate deficit, such as during prolonged fasting, starvation, periods of intense exercise, untreated type I diabetes etc., the liver converts’ fat into fatty acids and ketone bodies (the water soluble molecules acetoacetate, hydroxyl butyrate and acetone are together called the ketone bodies). This process is called ketosis.
The aim of ketogenic diet is to induce ketosis in the body by creating a deficit of carbohydrates. When you are on a ketogenic diet your body uses ketones as the primary energy source instead of glucose.
Ketosis induced by nutritional modifications such as by following ketogenic diet is safe. However, ketoacidosis, a severe form of ketosis, caused by diseases such as diabetes type 1 and type 2 and alcohol addiction is a dangerous medical condition that needs medical help. The amount of ketone bodies formed in ketoacidosis is 3-5 times more than that formed due to nutritionally induced ketosis. It is best to aim for moderate level of ketosis for optimal weight loss (1-4).
Benefits of ketogenic diet
Ketogenic diet has been shown to provide positive improvements in disease conditions such as epilepsy, heart disease, cancer, Alzheimer’s disease, Parkinson’s disease, polycystic ovary syndrome, acne and brain injuries. Ketogenic diet also improves insulin resistance because it lowers the glucose levels in the body. It has also been found that ketogenic diet can cause prolonged weight loss compared to other diets (4, 5).
Foods that are included in ketogenic diet (6, 7)
- Fats: Saturated fats (butter, ghee, coconut oil, tallow, lard, duck fat, goose fat, chicken fat), monounsaturated fats (avocado, olive oil), polyunsaturated fats (fatty fish and sea food)
- Grass fed meat, wild caught fish and sea foods, pastured eggs, gelatin, pastured pork
- Vegetables: Leafy greens (spinach, lettuce, chives, Swiss chard etc.), cruciferous vegetables (kale, radishes etc.) celery stalk, cucumber and summer squash
- Fruits: Avocado
- Mayonnaise, mustard, pesto, pickles, fermented foods
- Water, coffee, tea
- Whey protein, egg white, gelatin
- Spices and herbs
- Increase your consumption of electrolytes specifically potassium as keto diets tend to lower sodium and potassium levels in your body
- Indulge occasionally on vegetables such as tomatoes, pepper, eggplant, onion, garlic, mushroom, winter squash, okra, bean sprouts, sugar snap peas, berries, coconut, olive oil, macademia nuts, pecans, almonds, walnuts, sunflower seeds, pumpkin seeds
Foods that are excluded in ketogenic diet
- Completely exclude grains, factory farmed pork and fish, processed foods, artificial sweeteners, refined fats and oil, milk, tropical fruits and sugar from your diet.
Types of ketogenic diet (3)
- Standard ketogenic diets This is a low carbohydrate, sufficient protein and high fat diet. The diet plan is made of 75% fat, 20% protein and 5% carbohydrates.
- Cyclical ketogenic diet In this diet, days on ketogenic diet alternates with days on high carbohydrate diet. Usually in this diet plan 5 days of ketogenic diet is followed by 2 days of high carbohydrate diet.
- Targeted ketogenic diet In this diet you can add carbohydrates to your diet when you workout.
- High protein ketogenic diet This is similar to the standard ketogenic diet except that this diet contains more protein. The diet plan includes 60% fat, 30% protein and 10% carbohydrates.
The standard ketogenic diet and the high protein ketogenic diet are commonly used.
How to check if your ketogenic diet plan is working? (8, 9)
Since you are restricting carbohydrate intake and increasing your fat intake while following ketogenic diet, large amounts of ketone bodies are generated. Acetone is one of these ketone bodies that is secreted in the urine and breath and not used by the body.
Ketone breathalyzer: Acetone in the breath gives a fruity odor to the breath. During the first few weeks on ketogenic diet people often complain of fruity odor in their breaths. If you sense a fruity odor in your breath after starting the diet then you can be sure that the diet plan is working. However, the odor usually disappears within a few weeks of being on the diet. Increasing your water intake has been found to reduce the fruity odor. Ketones (acetones) in the breath can be measured by a breathalyzer. This is an inexpensive method for measuring the extent of ketosis in the body. Ketonix acetone breathalyzer is a commonly available option.
Measurement of ketone levels in the urine: An accurate and easy way of confirming that ketogenic diet is working is by measuring the ketone (acetone) levels in the urine. The ketone urine testing strips is a convenient method for checking your ketone levels in the urine. When exposed to ketone bodies, the strip changes color indicating the presence of ketones in the urine. The test kit comes along with a color guide that indicates the intensity of ketosis. Ketostix is the commonly available brand of ketone urine testing strips. In ketostix, the strip on exposure to urine containing ketones changes color from beige to purple. However, it has its share of disadvantages. The test can show false positive results when you are dehydrated while drinking a lot of water dilutes your urine and the test shows false negative results.
Measurement of ketones in the blood: Blood tests are the most accurate way for detecting ketosis but they are expensive compared to the urine tests.
However, if you have been following ketogenic diet and have been noticing visible results then it is not mandatory that you check your ketone levels.
Who should be carefully monitored while being on ketogenic diet? (10)
Ketogenic diet has numerous health benefits but there are certain medical conditions that are not favorable for following ketogenic diet.
- The enzymes from the gallbladder are essential for fat digestion. Therefore, patients with a gallbladder disease or who have had their gall bladders removed should follow the ketogenic diet only after proper medical advice.
- People who have metabolic disorders that disrupt their fat metabolism should seek medical advice before starting a ketogenic diet.
- People suffering from pancreatic insufficiency should also start ketogenic diet only after taking a doctor’s advice.
- Pregnant women should also carefully consider whether ketogenic diet is beneficial for them by consulting their doctors before starting the diet.
- Though ketogenic diets are beneficial in anorexia, patients suffering from anorexia should start the diet only after medical advice and they should be carefully monitored while on the diet.
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6. Complete Keto Diet Food List: What to Eat and Avoid | The KetoDiet Blog [Internet]. KetoDiet. 2015 [cited 2017 Jun 30]. Available from: https://ketodietapp.com/Blog/post/2015/01/03/Keto-Diet-Food-List-What-to-Eat-and-Avoid
7. Ketogenic Diet Food List: Everything You Need to Know [Internet]. Ruled Me. 2013 [cited 2017 Jul 1]. Available from: https://www.ruled.me/ketogenic-diet-food-list/
8. Ketosis & Measuring Ketones | The KetoDiet Blog [Internet]. KetoDiet. 2013 [cited 2017 Jun 30]. Available from: https://ketodietapp.com/Blog/post/2013/11/30/Ketosis-Measuring-Ketones
9. How to detect ketosis [Internet]. 8fit. 2015 [cited 2017 Jun 30]. Available from: https://8fit.com/nutrition/how-to-detect-ketosis/
10. Is the Ketogenic Diet Safe for Everyone? [Internet]. Diagnosis:Diet. 2014 [cited 2017 Jun 30]. Available from: http://www.diagnosisdiet.com/ketogenic-diet-safety/