Further thoughts on IF
To understand the basis of IF for weight loss we need to understand how fat is mobilised (something I had forgotten).
After a feed, insulin and fatty acids are elevated (NB: this is known as the post prandial phase - more nutrients are being stored than are being released from storage). The body is in the fed state and there's zero fat burning going on. The body is relying completely on glucose oxidation during the hours following the meal - one thing to remember here is that carb oxidisation prevents fat oxidisation so if no carbs are present fat oxidisation would presumably continue unabated (protein oxidisation is a separate thing and, providing it is moderate in quantity, would have no impact on fat oxodisation). (NB: Protein oxidisation is dependent on the amount of protein being ingested & there is a time lag so over eating or under eating protein slightly on one day should not affect oxidisation levels. In theory one could under eat on a DD & over eat on an UD slightly & get away with it whilst remain in NK & not affect LBM - one to test with the ketone strips)
One way of measuring this is via the respiratory quotient (RQ). An RQ of 1.0 denotes pure carbohydrate metabolism ("storage mode"), while 0.7 denotes pure fat metabolism. To put this into perspective, consider that RQ is 0.95-1.0 for about 1.5-2 hours after a meal, 0.82-0.85 after overnight fasting (12hrs) and 0.72-0.8 after 16 hours of fasting.
As the hours go by and the nutrients from the meal are done being absorbed (NB: Post absorptive stage - hormone levels change and the body starts shifting to an overall catabolic state ie the body is releasing more nutrients from storage than are being stored), RQ drops in conjunction with insulin. There's a shift towards fat burning and mobilization of stored fat.
I have been re-reading Mark’s take on IF.
Why Fast: Part 1 Weight Loss Is Intermittent Fasting Healthy
How to: Intermittent Fasting Women and Intermittent Fasting
He suggests pure fat taken during a fast will not take you out of the fast but will slow body fat oxidisation (obviously) GOOD!!
He also suggests studies have shown IF may not work as well for women as for men re weight loss BAD!!
The most useful thing I have found though is post from Martin Berkhan of leangains.com
I also read a study which suggests IF does not affect RMR & another which says it is as effective as CR but less painless. Also I read somewhere that walking in the 4-6hrs of optimum fat burning in a fasted state will also elevate fat burning in a to a new levelMy research has indicated that the ideal state of fat burning is reached after 12-18 hours of fasting. Coupled with high levels of catecholamines, increased blood flow to stubborn regions, and low insulin for a2-receptor inhibition, this time interval is the "golden age" of stubborn fat mobilization.
Let me just explain real quick what I mean by the ideal state of fat burning. Studies have examined free fatty acid (FFA) oxidation from anywhere between the overnight fasted state to three days of fasting. While FFA oxidation increases the longer time you spend in the fasted state, the contribution of fatty acids to whole body fat oxidation changes.
In short-term fasting there's a significant increase in subcutaneous FFA oxidation. That's just a fancy way of saying that you're mainly burning body fat and nothing else. For up to 14-20 hours* after a 600-calorie meal in normal-weight subjects, fat is only mobilized from body fat stores in resting individuals.
* 14-20 hours in a completely sedentary state should easily equal 12-18 hours in real life.
Past this time point, fat burning increases further. That goes without saying. But it's not necessarily the type of fat you're after that you'll be burning. Somewhere in between the 10- and 30-hour time point, the oxidation of intramuscular fat increases greatly, but no increase is seen in subcutaneous fat. Subcutaneous fat simply can't keep up with demand, so you're playing a game of diminishing returns if you push the fast too long.
So now I understand better why people are aiming for 1 meal per day & why incorporating the full ADF protocol may be better than 5:2.
I still want to get the coconut oil in daily & I am concerned about eating 1 large meal a day (memories of all those years I only ate once a day & put weight on (OK it was SAD, lots of cals probably & some alcohol but still). Won’t this keep the stomach large to accommodate it? Mark B talks about timings based on a meal of 600 cals. A larger meal would take longer to digest I assume so throw all the timings out.
Until I can afford to get 6mths worth of 4-weekly cycles of RMR & BF Calliper testing going (there’s a place just 6 miles away that does it Yes!!), a GoWearFit toy or equivalent & enough ketone blood testing strips for 6 mths, any more thoughts re NK is a waste of time as \I have no idea if I’m actually in it. I will continue with the level of Pg I am currently using (just in case) Cg is not an issue any way. But I am fed up with forcing down possible unnecessary fat for the sake of it.
In the meantime, given the long term health benefits of IF, regardless of the weight loss (or not) I am inclined to start working towards my own version of IF now.