This stuff seems complicated at first, but don’t worry! This very article will bestow a lot of wisdom upon you. But first, the Wiki explanation:
When glycogen stores are not available in the cells, fat (triacylglycerol) is cleaved to provide 3 fatty acid chains and 1 glycerol molecule in a process known as lipolysis. Most of the body is able to use fatty acids as an alternative source of energy in a process called beta-oxidation. One of the products of beta-oxidation is acetyl-CoA, which can be further used in the citric acid cycle. During prolonged fasting or starvation, acetyl-CoA in the liver is used to produce ketone bodies instead, leading to a state of ketosis.
During starvation or a long physical training session, the body starts using fatty acids instead of glucose. The brain cannot use long-chain fatty acids for energy because they are completely albumin-bound and cannot cross the blood–brain barrier. Not all medium-chain fatty acids are bound to albumin. The unbound medium-chain fatty acids are soluble in the blood and can cross the blood–brain barrier. The ketone bodies produced in the liver can also cross the blood–brain barrier. In the brain, these ketone bodies are then incorporated into acetyl-CoA and used in the citric acid cycle.
The ketone body acetoacetate will slowly decarboxylate into acetone, a volatile compound that is both metabolized as an energy source and lost in the breath and urine.
Ketosis In A Nutshell
Ketogenic diets are basically diets very high in protein and fat, and very low in carbs – VERY low! Ketogenic diets have long been proven to be useful for fat loss. Not only are they useful for shedding unwanted fat, but keto-based diets are pretty damn good diet for sustaining your hard earned muscle. Catabolism is kept to a minimum, thanks to all the protein you’re ingesting. Yummy!
Now this all sounds great. But is there a drawback? Of course there’s a drawback. If it seems to good to be true, then it usually is. While on a ketogenic diet, your high intensity exercise routine will take a hit; a big hit!
When involved in a high intensity sport or activity, the primary source of energy is carbs. Ya cut out carbs, ya cut down the ability to do sustainable high intensity work – it’s that black and white.
This article from SimplyShredded.com talks about some science behind the ketogenic diet and what-have-you. It’s a good article. ( Of course it’s a good article – if it wasn’t a good article, we wouldn’t be talking about it! )
Although ketogenic diets are useful for fat loss, while simultaneously sparing muscle loss, they have one significant drawback: they cannot sustain high intensity exercise. Activities like weight training can only use carbohydrates as an energy source, ketones and free fatty acids (FFA) cannot be used. Therefore the lack of carbohydrates on a ketogenic diet will eventually lead to decreased performance in the weight room, which may result in muscle loss…
You Can Have Carbohydrates on a Ketogenic Diet BUT…
But wait! There’s a twist! The article not only promotes ketogenic diets, but it actually discusses the proper way to introduce carbs into the ketogenic diet, so you can reap the benefits of being in ketosis, as well as have the sustained energy for the high intensity exercises you do (or should do). Yipee!
“Carbs on a ketogenic diet? Blasphemy!” Slow down there cowboy.
You can still be in the state of ketosis while adding some carbs to your diet regime. The key is proper planning of when to add those carbs. You have to plan how many grams of carbs you’ll be ingesting that day, and when.
It’s not a “free-for-all of carbs just as long as you meet your macros.” Didn’t think you’d get off that easy, did ya?! Well then, here’s what the boys at SimplyShredded.com have to say about carbing up on a ketogenic diet:
Arguably the two most critical aspects of a successful carb-load are the duration of the carb-load and the total amount of carbohydrates consumed during this time period. In brief, to achieve optimal glycogen levels, both the duration of the carb-load and the amount of carbs eaten must be correct. The rate limiting step in glycogen resynthesis appears to be activity of the enzymes involved in glycogen synthesis (1). Regardless of carbohydrate intake, there is a maximal amount of glycogen which can be synthesized in a given amount of time. That is to say, consuming all of your carbohydrates in a 4 hour time span, with the goal of returning to ketogenic eating that much sooner, will not work. Only when the proper amount of carbohydrates is consumed over a sufficient period of time, can glycogen compensation and/or supercompensation occur. Following exhaustive exercise and full glycogen depletion, glycogen can be resynthesized to 100% of normal levels (roughly 100-110 mmol/kg) within 24 hours as long as sufficient amounts of carbohydrate are consumed (1,2).
WHEN to Eat Carbohydrates on a Ketogenic Diet
And they BETTER be good carbs, not just any carbs. The type of carb consumption while on a ketogenic diet is of the utmost importance, bar none! How many grams exactly? Well…
The carb-up should begin immediately following training. A delay of even 2 hours between the end of training and the start of the carb-up causes glycogen resynthesis to be 47% slower than if carbs are consumed immediately. (10,12). Ideally you should consume a large amount of liquid carbs immediately after training. A good rule of thumb is to consume 1.5 grams of carbs/kg lean body mass, with approximately one half as much protein, immediately after training and then again two hours later.
Post Workout – You’re Allowed Some Simple Carbs After a Workout
Before we say bye bye to this post, one more point should be touched upon. That point is carb consumption post-workout. It is no secret that consuming proper carbs post-workout, in the proper window, has drastic (in a postive way) results for restoring your depleted glycogen stores.
There it is folks. Laid out for you in the simplest terms possible. This is just a piece of the science behind a ketogenic diet, so head over to this SimplyShredded.com article, and tickle your brain with an abundance of great info!