Continuing the discussion from NuSI metabolic ward study on low-carb & the insulin hypothesis:
Thanks! I’d certainly like to experiment with this. It’s good to know the lipid metabolism doesn’t go away with the addition of a few carbs (the keto discussions talk a lot about falling out of nutritional ketosis with a carb meal). Granted I’m not really seeking nutritional ketosis, but rather merely to lower my RQ at moderately high heart rates (75%-85% max HR). I’m fine not carbo loading the night before a marathon (my GI tract is much more predictable after 24-36hrs of Soylent)… But it is nice to know I could start in with the gatorade and/or gels early in the race or at the very start without critically damaging my potential lipid metabolism. It’s a tough balance though, if I take sugar my RQ will certainly shoot up right?
One other thing I noticed on the two latest marathons was that my HR went up in the 2nd half (about the same time I started the sugar)… I had been trying to maintain a 145-150 HR but by mile 18 or 19 I was willing to push 155-160 to see how that would last. I’m not sure how much of the late kick from 24-26 was due to the sugar vs just psychological (being near the finish line). But I’ve had many other marathons where “hitting the wall” around mile 20 leads to nothing but progressively slower and slower miles…
For general training though, it would be interesting to know for example:
What is the RQ for a 30 minute workout at 150 pbm HR after
A: a week of eating 40% fat 40% carb 20% protein
B: a week of eating 50% fat 30% carb 20% protein
C: a week of eating 60% fat 20% carb 20% protein
D: a week of eating 70% fat 10% carb 20% protein
It’s too bad that it’s so hard to measure the RQ although I suppose if I found a local lab that could hook me up on a treadmill for a reasonable price I might try it…
edit: btw Respiratory Quotient (RQ) is a measure of the carbon dioxide exhaled relative to the oxygen inhaled. 0.7 indicates nearly complete fat oxidation whereas 1.0 is nearly complete carbohydrate oxidation.
Also, here are my last two marathons both were preceded by a mostly 1.5+oil and 2.0 diet (45-47%fat) with the last few days prior to the marathon being straight 1.5 (40% fat). At Eugene I actually had some diluted 1.5 stashed at mile 9 as well…