My understanding is that one of the principles behind CBL is that muscular insulin sensitivity is relatively low in the morning and relatively high in the evening. Is that true? Why?
My own layman's explanation would be that using your muscles raises their insulin sensitivity, and so after sleeping all night and not using them at all, their sensitivity would be low, but then as you use them throughout the day, it increases. Though, I'm not sure if it's actually only very intense exercise (e.g., lifting heavy weights) which raises muscular insulin sensitivity rather than normal daily movement, and I believe Kiefer would say the low to high insulin sensitivity swing happens even on rest (non-lifting) days.
Or, is this caused by swings in other hormones that are tied to the circadian rhythm? Which and how?
Is there any evolutionary medicine explanation for why this insulin sensitivity swing happens?
Caveat: I haven't read either of his books yet. All I know is based on reading his website and listening to interviews with him.
asked byMike_T_1 (9402)
Get FREE instant access to our Paleo For Beginners Guide & 15 FREE Recipes!
on January 11, 2013
at 10:45 PM
You have it reversed. Kiefer says Insulin sensitivity is highest in the morning, which is why lot's of people recommend eating carbs in the morning, but get it wrong. If you don't eat in the morning, and break fast with no carbs, you remain in a fat burning state, until your body becomes insulin resistant later in the day... which sounds bad, but then you strategically do resistance training later in the evening to bring GLUT-4's to the muscle cells (Glucose Transporters - which suck up glucose and bring them to the cell, even with a lack of insulin) and then you eat your carbs. Your fat cells will then be resistant, and muscle cells will be covered with GLUT's so the carbs go preferentially to muscle, all while the whole morning your burning fat.
I haven't read keifer's books yet, as CBL 2.0 will be coming out so I'm waiting for that, but, I have read every article 2-3x and annotated them, listened to his podcasts/interviews with both Dave Asprey and Robb Wolf, listened to and took notes on his first 5 BioJacked episodes, and went through the forums thoroughly.
This is from his Fixing the Damage PT.2 Article: "Taken without an understanding of how the body works this seems contrary to current wisdom, which is based in fact. Fact: the body is more sensitive to insulin in the morning. A logical corollary, often called wisdom: eat the majority of your carbs early in the day because the body uses more of the carbs and uses them faster. The fact is just that, so disputing it is not an option, but I have a problem with the corollary, however logical it may appear. To understand the breakdown in sensibility, we need to understand how cells use carbs."
Read his articles and check his citations and you will see why these hormonal swings happen through out the day, it does have to do partially with what you touched on. Hope this helps clarify things a bit.