5/10/2009 1:07pm, #161
Speaking of celiac, it seems to me that the celiac response would be a good first-order approximation (systematic overestimate) of delivered lectins, and so the grocery-shopping decision-making process could be similar. Thoughts?
Rate of hydrolysis is a parameter of free glucose available to be absorbed, and free glucose is a parameter of serum glucose response, so it follows that GI and HI would be correlated. That's the good news.
Bad news #1: Take a look at Fig. 1 of the Goni study. The correlation they're hanging their hat on is total starch hydrolysis percentage at 90 minutes, which is within a hair of the final equilibrium point for all the starches they showed. And given how energetically unfavourable spontaneous condensation back into polysaccharides is, that "equilibrium" is really more of a "completion". So... they rediscovered resistant starch? Ouch.
Bad news #2: GI is still... problematic. I want to see what other, complementary tools we can come up with for HI, to start quantifying the other variants:
Yes, and also insulin response. The blood glucose curve is the difference between inflow and uptake, and AUC will be reduced by the product (actually integral, but whatever) of uptake magnitude and time. Still linear, but linear with a constant offset... which messes up the ratios to glucose/white bread.
And, of course, insulin stimulation and sensitivity are a whole other can of worms. Realistically, even if we lump all the digestive tract factors together, we'd still want to measure blood glucose at the portal vein to sidestep uptake altogether - slice the Gordian knot, as it were.
in general, I think). It's nice.
5/10/2009 3:31pm, #162
“Most people do not do, but take refuge in theory and talk, thinking that they will become good in this way” -- Aristotle, Nicomachean Ethics, II.4
5/10/2009 5:18pm, #163
If I were running the tests, I'd be curious about two things (well, three, but I'm assuming that the resistant/digestible starch amounts are already known):
1) Saturation point for the enzyme
2) The characterization of the curve (the Michaelis constant?)
From this, we can get all sorts of useful stuff. In particular, given an initial quantity of food (and enzymes), we'd have what you described - maximum rate that the digestive tract could be dumping glucose onto the glucose transporters at a given time. Or we could turn the graph sideways and look at minimum time to deliver a given quantity of sugar.
But just taking the final percentage is silly.
5/10/2009 7:48pm, #164
On a... less academic note, I'm on day seventeen of an Anabolic Diet metabolic shift (<30g net carbs/day, 60/40 calories from fat/protein - daily breakdown is available here). I've been tracking each of these on a morning/evening basis:
-get up/lie down (wake/sleep approx.)
-two different BIA scales' readings
-diameter of my left upper arm, left thigh, and beltline
-skinfold as per the AccuMeasure instructions
-body composition photographs: forward and sideways arms-out and arms-down
Thus far, the verdict on the diet is... nothing's really happened yet. The BIA scales have shown curves to bad and then back to good, the direct measurements are within the margin of error and day-to-day variation, and I'm not really seeing a whole lot from the body composition photos.
That said, I've learned quite a bit about the process:
-The scales diverge by about three pounds on average.
-The cheap BIA scale is convinced that my overnight weight change is water loss.
-The expensive one is convinced that it's fat loss. (Its muscle mass estimate is surprisingly consistent overnight and throughout the day)
-When it comes to tripods, you get what you pay for.
-The compact fluorescent I have in my room takes a while to warm up, and during this period, its brightness and colour vary greatly.
-Roof-mounted lighting shows more definition (whether or not it's real) than front (flash) lighting.
-In addition to markings on the floor for the camera and foot positions, put "targets" on the pictured wall to scale and rotate body composition images by.
-Still don't think I've got posture controlled well enough to be really scientific about the body comp shots. Thinking about leaning against the wall, but that poses its own problems.
-Skinfolds are tough to take - a bit of variation in finger/caliper positioning introduces a lot of error. I'm thinking I might revise my technique such that the finger positions are more clearly defined (right now I've just got a pair of Sharpie dots to mark the caliper points).
-I look like absolute Hell first thing in the morning.
Anyways, I'm not entirely sure what my next step should be. Head's holding up pretty well while I bike to/from work, so I might be able to resume lifting in June, which would be nice. Haven't done a carb load yet, so presumably I'll do one of those next weekend. Not entirely sure about the mechanics of cutting fat.
5/12/2009 11:25pm, #165
Okay, so I found oat bran at the grocery store today, but of the 10g carbs, only 2g was fiber. I assume it's not the same thing?
Also, something odd I noticed today - was looking at the bottles of corn syrup, and they claim that although they've got something like 34g carbs/30mL serving, only 11g of that is sugar. Which is absurd, given that the first three ingredients are "glucose, glucose-fructose, water". What the Hell else could there be in it? (And why is fructose there?)
5/13/2009 11:35pm, #166
So Biochemistry 200 started today. It was a lot of fun. Hopefully I'll be able to keep up a full head of steam for the rest of the class.
And in case anyone else was wondering, histidine is classified as a positively-charged amino acid because its imidazole group can take on a positive charge at the "double-bonded" nitrogen (forget about Kekule for a while).
Does anyone (I'm looking at you, Jack Rusher) have any thoughts about dietary fat's effects on insulin sensitivity? A cursory look at a few abstracts makes it sound like there's a relationship with quantity and type. It doesn't really pass my initial smell test, although given that it seems there are really three types of insulin sensitivity (adipose, muscular and hepatic), I suppose it could have a differential effect?
5/14/2009 7:38pm, #167“Most people do not do, but take refuge in theory and talk, thinking that they will become good in this way” -- Aristotle, Nicomachean Ethics, II.4
5/14/2009 11:58pm, #168
this (shipping is liable to be a bitch, though). Do any of the mail-order places you know of ship to Canada?
The literature I stumbled into was mostly about saturated fats. Actually, it's kind of funny you mentioned omega-3s, because one study I ran into considered saturated, unsaturated and omega-6 but not omega-3. (Will post link if I can find it)
Furthermore, percentage of long-chain omega-3 fatty acid in phospholipid measured in red quadriceps correlated highly with insulin action in that muscle (r = 0.97).
In rats fed high-fat diets, replacement of only 6 percent of the linoleic omega-6 fatty acids from safflower oil with long-chain polyunsaturated omega-3 fatty acids from fish oil prevented the development of insulin resistance. The effect was most pronounced in the liver and skeletal muscle, which have important roles in glucose supply and demand.
And I'm not entirely sure what to make of this...
Fat feeding significantly reduced suppressibility of hepatic glucose output by insulin after both 3 days and 3 wk of diet (P less than 0.01). However, a significant impairment of insulin-mediated peripheral glucose disposal was only present after 3 wk of diet. Further in vivo [3H]-2-deoxyglucose uptake studies supported this finding and demonstrated adipose but not muscle insulin resistance after 3 days of high-fat feeding.
At present, it appears to me that in terms of body composition, the effects of insulin resistance are not uniform. Insulin resistance in adipose cells (ceteris paribus) should lead to reduced fat storage, whereas insulin resistance in muscle tissue should lead to a reduced nitrogen balance. I'm looking for convincing evidence of asymmetries between them. In plain English, trying to figure out how to stimulate muscle growth without fat growth, or fat loss without muscle loss.
I've been getting a fair bit of my dietary fat from walnuts lately - that adds up to a lot of linoleic acid. Might switch to olive oil if I can work out the logistics of it. Not sure I want to start tracking my fatty acid intake more specifically, but at bare minimum, saturated/unsaturated should be doable.
Found out today that my biochemistry prof used to be a competitive powerlifter. Nifty, eh?
A metric that came up a few times in the T-Nation thread about the Anabolic Diet is waking temperature. Might be worth tracking. What do y'all think?
(I've also pondered doing a waking heart rate, but I think that one might be too contingent on how jarring my wakeup was...)
5/15/2009 12:17am, #169
So I've been asked about sleep. Appropriate in two ways:
-I've spent years of my life with absolutely calamitous sleep patterns, and
-I should get to sleep pretty soon now, actually
The vast majority of my approach was psychological/behavioural.
You have to want to sleep. All the sleep aids in the world won't help you if you're watching "just one more" YouTube video.
You have to remove obstacles to sleep. Light, distracting sound, drafts, too hot or cold, a rambunctious bedmate... anything that makes the sleep environment the least bit "interesting". This includes your alarm clock.
Impose discipline in terms of wake times first, rather than sleep times. If you force yourself to go to bed when you're not sleepy, you may wind up laying awake all night. Instead, once you've established that you want to sleep, simply head to bed when your body starts hinting at it, but set an absolutely inviolate time that you will wake up, get out of bed, and stay awake after.
To avoid ruining your life for the transition period, make only incremental changes to said wake time rather than bumping it up all at once.
Establish buffer zones for anything that might keep you awake - diuretics, stimulants, gastrointestinally-influential foods (heartburn, bloating, or otherwise), and even water. Get what you need before the cutoff such that you'll have time to completely process it before sleep.
Melatonin supplementation is great, but do it well before bed. I've heard suggestions of dosing as much as five hours before bedtime, which seems a bit much to me, but taking it right before lights-out hasn't been as effective in my experience.
Effects of foods may vary. I find that milk protein isolate tends to make me a bit sleepy during the day. I don't know whether taking it just before bed has any real effect, but it certainly hasn't made sleep any harder.
On a carb-restricted diet, scheduling carbs for the end of the day (for optimally-timed sluggishness) is suggested (IIRC) by both Di Pasquale and Faigin.
And now I'm off to bed. Hope this helped.
5/15/2009 12:10pm, #170
The best source of long-chain omega-3s is the oily/fatty flesh/eggs/milk fat from animals who've lived on decent feed (example: corn fed cows shift to omega-6s in their fatty acid reserves, just like corn oil fed humans). Sadly, this kind of meat/fish/dairy demands a price premium. Speaking of which, I'm off now to cycle to the farmer's market to buy some... :smile:“Most people do not do, but take refuge in theory and talk, thinking that they will become good in this way” -- Aristotle, Nicomachean Ethics, II.4