Carb cycling 101Carb cycling is exactly what it sounds like, you cycle the amount of carbohydrates you eat each day, normally by eating high carb on workout days and low carb on rest days. While individual programs vary, most follow a structure similar to the one below:
Taken from: veggiereader.wordpress.com
My primary issue with carb cycling safety is the level of carbohydrates on the low carb days for women, and to a lesser extent men. Let's take a look at the numbers for a 150lbs woman. On high carb days, this woman will consume 210g of carbohydrates and on low carb days she will consume 90g of carbohydrates. This may not seem like a big deal, but when you consider the brain uses 120g of glucose just to keep you operational everyday you can see a woman could easily put herself in to a brain glucose deficit.
A woman who is not ketoadapted(It's impossible to become ketoadapted when you consume a carb level higher than 50g/day in a 1 week period) will burn approximately 1500 calories just to stay alive with 150g coming from carbohydrate. This is merely to keep her alive, this does not include physical activity which will increase this number considerably unles she is ketoadapted. So if she stays in bed and doesn't move she is in a 30g glucose deficit. To make up for that deficit, she will have to call upon cortisol to make glucose from non-carbohydrate sources. If she does any sort of physical activity, even walking, she will use some of the glucose she made from carbohydrates and the glucose her brain would use later in the day would be used up. Cortisol could be called in to action to make more glucose, more than likely later on in the day or at night as the brain runs out of energy, especially if intense exercise is part of your weekly plan. Having cortisol secreted late in the evening or even in the middle of the night is bad for your circadian rhythms and will disrupt sleep. It would even be possible to go in to a glucose deficit on training days if you train intensely enough and a 200lbs male would be able to achieve a considerable glucose deficit at 180g on low carb days.