The ketogenic team will suggest the most suitable diet for you or your child based on age, activity, normal food intake, likes and dislikes, etc. All versions of the diet are very high in fat, low in carbohydrate and usually require a vitamin and mineral supplement. Regular monitoring to check tolerance, growth and general health will be arranged.
The first two types of ketogenic diet available were the Classical and the Medium Chain Triglyceride (MCT) diet. More recently the Modified Atkins Diet (MAD) and Low Glycaemic Index Treatment (LGIT) have been used with success. Your ketogenic team may advise you on a personalised ketogenic diet which incorporates some of the practices and features of these different versions to meet your individual requirements and lifestyle needs, this is called a modified Ketogenic Diet (mKD).
Classical Ketogenic Diet
This is based on a ratio of grams of fat to grams of carbohydrate and protein. For example, a 4:1 ratio equates to 4g of fat to every 1g of protein and carbohydrate combined. In terms of energy, this means that 90% of calories comes from fat and the remaining 10% from protein and carbohydrate combined. Your ketogenic team will advise on what ratio suits you or your child’s needs. In this diet all foods must be carefully prepared and weighed on digital scales. Every meal and snack must be in the correct ratio for the individual and must be eaten in its entirety for the diet to be most effective.
The pie charts highlight the proportion of fat to carbohydrate and protein in of the ketogenic diets in comparison to a normal diet.
MCT Ketogenic Diet
This diet uses medium chain triglycerides (MCT), a type of fat derived from coconut and palm oil alongside the long chain triglycerides (LCT) that is normally present in food. MCT is taken either as an oil or an emulsion. MCT has the advantage it can be used by the body (metabolised) a lot quicker than LCT and produces more ketones per gram of fat. As ketones are more readily available in this version of the ketogenic diet, less total fat is needed, meaning more carbohydrate and protein foods are allowed. Generally 30-60% of energy requirements will come from MCT. However, the exact amount for you or your child is decided by the ketogenic team.
Usually, MCT is introduced slowly into the diet as in some individuals it can lead to tummy upsets, and tolerance will be monitored by your ketogenic team. A source of MCT is required at each meal or snack and although this version of the diet provides greater flexibility to allow more protein and carbohydrate in the diet, like the classical ketogenic diet, meals still need to be planned, calculated and weighed.
Modified Atkins Diet (MAD):
This diet is a modification of the Atkins diet used for weight reduction. It was designed to be more flexible and less restrictive than the classical and MCT versions of the ketogenic diet, although it is not an easier option. Carbohydrate is very restricted at 10g per day initially (increasing to 15-20g per day after 1-3 months), protein is not limited (but too much is discouraged) and foods high in fat must be eaten liberally and with each meal. You may also be given a guide as to how much fat needs to be eaten each day and at each meal. The MAD is frequently used in older children and adolescents who may not cope well with the dietary restrictions of the classical or the MCT ketogenic diets. There is not so much weighing involved and food exchange lists provided from your ketogenic team can be used in this diet.
Modified Ketogenic Diet (mKD):
The mKD is similar to the MAD but has a more structured approach. It is restrictive, but has a slightly more generous carbohydrate allowance (especially when starting the diet) which is evenly spread over meals and snacks. Your ketogenic team will decide on the amount of carbohydrate suitable for you. Food choices are designed to be flexible and when undertaking the mKD guidance and structure will be provided on food selection and portion sizes by use of an ‘exchange ‘or ‘choice’ system for foods providing fats and carbohydrates. These are typically weighed out, especially at first. This, together with advice on moderation of protein foods, and meal plans, helps ensure an appropriate macronutrient and energy intake for you or your child.
Low Glycaemic Index Treatment (LGIT):
This version of the ketogenic diet takes into account the type of carbohydrates that are eaten and how they affect the glucose level in the blood. The glycaemic index (GI) is a measure of the effect of carbohydrates on blood sugar levels, classifying them by their potential to raise blood glucose on a scale from 0-100. The LGIT includes foods that have a GI value of less than or equal to 50 which means the carbohydrate is more slowly released and absorbed during digestion therefore preventing a spike in blood glucose levels. The carbohydrate allowance is 40-60g/day (which includes fibre, unlike any other of the ketogenic diets) and must be evenly distributed throughout the day. This level of carbohydrate still ensures that the body burns fat as its main energy source. Fat supplies 60% of daily energy requirements and should be eaten with every meal and snack and a moderate protein intake is encouraged. Approximate portion sizes are used, although foods can be weighed and measured and guidance on low GI food choices and amounts is necessary.
If the ketogenic diet is new to you or your child it may seem quite challenging and confusing to start with, but with time and the help and support of your ketogenic team it should become much easier.