Ketogenic diets are used for weight management purposes as well as therapeutically for a number of chronic health conditions including epilepsy, metabolic syndrome, MS, chronic fatigue syndrome, Alzheimer’s, Parkinson’s and cancer. The diet is high in fat, moderate in protein and very low in carbohydrates. Most people burn glucose from carbohydrates as their main fuel source. When you are on a ketogenic diet, your body makes a metabolic shift and it switches fuel source from carbohydrates to fat becoming the main source of energy.
This is likely the way our ancestors ate most of the year. During the summer and autumn months, they would likely have eaten large quantities of carbohydrates, gaining fat to see them through the leaner winter months. In the winter, the stored body fat supplemented their more restricted winter diet.
Using fat as the main fuel is called ketosis. Our ancestors are likely to have spent a large proportion of time in ketosis. A high fat, moderate protein and very low carbohydrate ketogenic diet causes the body to behave in a similar way to periods of restricted food availability.
Between meals, during fasting and strenuous exercise, blood glucose levels fall and fatty acids are released from adipose tissue and can be used to fuel the cells - except brain cells which are unable to utilise fatty acids directly. Fatty acids are converted in the liver into ketone bodies which can be used by tissues, including the brain, as a source of fuel.
Restrict your carb intake and wave goodbye to sugar and processed carbs
In order for the body to switch to ketosis, carbohydrate intake needs to be low, but the threshold is very individual. The more metabolically challenged your body is, the less carbohydrates you are likely to be able to handle (referred to as insulin resistance or carbohydrate intolerance). When embarking on a ketogenic diet, try going below 50 grams per day of net carbs. Net carbs is the amount of carbohydrate minus fibre, so there is ample room to eat plenty above ground, leafy vegetables as the fibre content will offset the amount of carbs they contain. Some people may need to go lower initially, possibly as low as 20 grams of net carbs per day. Others can tolerate eating more carbs whist still remaining in ketosis.
Carbohydrates should come mainly from above-ground vegetables (below ground vegetables are more starchy and therefore give a higher glycemic response), some nuts and seeds and small portions of low glycemic fruit, such as berries. Sugar and processed carbs are a no-go. These have little or no nutritional value. Once you start thinking of food as cellular fuel, this type of food will no longer appear as desirable.
Fat is your friend!
It is important to eat plenty of healthy fats to stay in ketosis. These include avocado, avocado oil, extra virgin olive oil, organic butter and ghee from pastured cows, coconut oil and MCT oil. Nuts (macadamia nuts and pecans have the highest fat content), seeds and duck fat are other sources of healthy fats. Don’t overdo it on the nuts as they are high in Omega-6 fats creating an imbalance in the amount of Omega-3 (anti-inflammatory) to Omega-6 (pro-inflammatory) fats consumed. There are other sources of good quality fat that come packed with protein, such as eggs from organic pastured hens, wild oily fish and organic grass fed beef – think the unpopular fatty cuts rather than the lean muscle meat.
MCT oil - quick access to ketones
MCT oil, especially the type that only contains fatty acids of the 8-carbon atom variety (caprylic acid), is very effective as it circumvents the digestive tract, goes straight to the liver where it is converted into ketone bodies, providing you with quick access to fuel in the form of ketones. MCT oil has a neutral taste can be eaten off the spoon or added to coffee, tea, smoothies or to your food. When adding MCT oil to the diet it is best to start slowly by taking one teaspoon per day initially to avoid any unwanted gastrointestinal side effects. It is a great way to beat cravings when you are weaning off carbs. Take a teaspoon of MCT oil 1-2 hours before the time you normally have your carb-crash.