The high-fat, moderate-protein, low-carb ketogenic diet has become a very popular conditioning tool for many local and international bodybuilders because of its power to burn fat while gaining muscle.
While not a new diet by any means, the rise in popularity of this diet has caused many athletes to reconsider their pre-competition nutrition choices.
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Low carb trigger
At a basic level, dieting forces the body to use fat stores instead of stored glycogen for fuel.
Due to the low carbohydrate intake prescribed by the diet and in the absence of glycogen, the pancreas releases glucagon, a catabolic hormone that has the ability to break down body tissues for energy.
The body is then forced into a state of ketosis when glucagon and carnitine convert stored fat into free fatty acids and energy substrates called ketones or ketone bodies. All of this is done in the liver through the Krebs cycle.
THE Ketone bodies then circulate and replace glucose as the body’s main source of energyfulfilling the various vital functions that glucose had in the body. As the level of ketone bodies in the blood increases and reaches a threshold, the body enters a state of ketosis.
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Keto Diet Guidelines
The classic ketogenic diet foods rich in carbohydrates are excluded such as starchy fruits and vegetables, bread, pasta, grains and sugar, while increasing consumption of foods high in medium-chain triglycerides – which are more ketogenic – and long-chain triglycerides.
By forcing the body to tap into fat stores for energy by drastically reducing the amount of carbohydrates you consume, bodybuilders have been able to drastically reduce their body fat percentages to meet their race preparation.
By following this diet, even for short periods of time, the body also becomes more efficient at mobilizing stored fat for energy.
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Muscle sparing effect
It is important for the preparation on stage, a situation Ketosis also appears to have muscle effectsprovided that your dietary protein intake and total calorie consumption are adequate and that your training volume is kept low and heavy.
This occurs as the body preferentially uses circulating ketones for energy, which limits protein gluconeogenesis – the process where muscle tissue is broken down (catabolized) into amino acids and converted into glucose.
In addition, the lack of carbohydrates and sugar in the diet limits the amount of insulin released from the pancreas into the body. This can increase lipolysis and release of free glycerol and reduce fat storage. Reduced insulin release also helps increase natural production of growth hormone and releases other powerful growth factors.
A high-fat diet is also more calorie dense. The fact that each gram of fat releases nine calories, as opposed to only four calories per gram of carbohydrate, means that energy from fat is also more efficient and will help boost energy levels.
Recycling your carbs
Regarding its application as a pre-race diet, many coaches advocate its use replenishes glycogen or periods of carbohydrate cycling to provide the energy needed to train at the correct intensity and volume ahead of a performance.
There are two specific techniques used in this regard, namely the cyclic (CKD) or the targeted (TKD) ketogenic diet.
- CKDs involve periods of high carbohydrate intake for 1-2 days, usually at the weekend or on rest days, followed by a minimal amount of around 30-50g of carbohydrate on the other days of the week. These “carbs” refill your muscle glycogen stores, giving your body the energy it needs to power through the next week’s workouts. If done correctly, without causing a glycogen “leakage” effect, this carb spike can trigger anabolic recovery and even muscle growth as the dieter exits the low-carb phase.
- TKDs plan carbohydrate-rich pre- and post-workout meals. This approach is ideal for those intense workouts where extra energy is needed. For example, on heavy training days, an athlete might consume 25g of carbohydrates with some whey protein 30 minutes before training and another 25-50g with protein afterwards. There are no carb days and carb intake is minimal for the rest of the day.
Starting a ketogenic diet
If you have never used a ketogenic diet your body should go through a process commonly referred to as a ‘metabolic shift’.
This is the process in which the body moves away from its dependence on glucose and learns to function properly using ketones as an energy source.
As glucose plays an important role in brain function, dieters often experience cognitive fatigue in addition to the physical fatigue associated with low glycogen levels. This adaptation process can take up to three weeks, but if after three weeks your body has not adapted, then it is generally recommended that you try another diet.
In general, the best way to get into ketosis is to start with a fairly high fat intake with small amounts of protein.
First-time users should also aim to include 100 grams of carbohydrates per day as part of the initial phase of their diet. The rest of their diet should consist of protein and fat.
Once your body has acclimated to this type of diet, start reducing your carb intake until you reach a state of ketosis. At this point, reduce your fat intake slightly and increase your protein intake.
It’s important to do it this way, as protein can affect the development of ketosis because a portion of your dietary protein intake can be converted to glucose.
The ideal pre-race ketogenic diet typically consists of 35-40% of calories from protein, 50-55% from fat, and the rest from carbohydrates.
Author: Pedro van Gaalen
When he’s not writing about sports or health and fitness, Pedro is most likely out training for his next marathon or ultramarathon. He has worked as a fitness professional and as a marketing and comms specialist. He now combines his passions in his role as managing editor at Fitness magazine.
