Why do some of these things land in my lap when life gets so busy? Over on Mercola's site, I've been tangling up a bit with Ron "Spiked Leptinade with my Science Krispies" Rosedale. Now I don't expect Rosedale to start following my blog or anything, but I did post links to certain posts over there to support my contention that carbs do NOT spike leptin. By any definition, they do not. Instead of recognizing this and backing off (and hoping nobody notices, a la Taubes), Rosedale has doubled down on his assertion that carbs spike leptin. In support of his contention, the science he offers up is ... drumroll please ... a more than decade old study on isolated cultured rat adipocytes. This wouldn't drip so with irony were it not for the fact that Rosedale shoves his massive clinical experience with live humans in yo' face every chance he gets. You see, I don't possess his vast clinical experience so I must be in error interpreting the whole blood v. plasma blood glucose level data in a 45+ year old study (more on that to come!!) Yet, when presented with a sampling of human data from clinical studies ... then Rosedale turns a blind eye. It gets worse. I called him on relying on this study to advance his point. His response? More of the same about how I don't know the science. Here's what he said:
@CarbSane; apparently you not only do not know the science, but you refuse to learn it also, even when spoon fed. Nutrients spike leptin significantly, typically much more than sleep; see article I posted for your benefit at start of this thread. It is one of many. I will repost;
The Effects of Insulin, Glucose, and Pyruvate on the Kinetics of Leptin Secretion Endocrinology 142: 3558–3562, 2001
"The purpose of this study was to determine whether the secretagogues, insulin, glucose, and pyruvate, enhance leptin secretion…For 60 min after the addition of secretagogues, leptin synthesis rapidly increases, leptin increases intracellularly by approximately 60% (P<0.05). After 60 min, leptin is significantly released from cells. At 120 and 240 min, secretagogues enhance leptin secretion into the medium by 35% (P < 0.05) and 40% (P < 0.01), respectively."
Yes, repost the same old isolated rat fat cell study. What about those humans you treat in clinical settings? This would be all fine and well were it not for the fact that we simply don't see postprandial leptin spikes in whole, real, live human beings ... aka you and me. In case anyone reads this post, let me repost for the record the original pp leptin and insulin graphic. (Top is women, bottom is men). I see some insulin spiking going on (left) but do you see a leptin "spike"?? Unless one redefines the term, I'm saying no. Indeed in the immediate postprandial period, 2 to 3 hours, leptin levels are "anti-spiked". Dietary nutrients suppress circulating leptin levels as seen in the plots. I have no idea why I even bothered to look further, but perhaps it's his insistence on the role of blood glucose levels in all of this. But a Google scholar search turned up this study: A High Glycemic Meal Suppresses the Postprandial Leptin Response in Normal Healthy Adults. Were I a cherry pickin' science journalist, I would probably have skipped right on by that title for fear of being confronted with contradictory evidence. But that's not me. I was intrigued. Well, it turns out the "response" is not that imaginary spike Rosedale speaks of ... turns out quite the opposite, though without the spikiness. Thanks to MM for the full text of this one. The subjects were all within 20% of normal body weight, glucose tolerant, and all that, included 6 men and 4 women aged 18-37. For two days prior to each test day, they were counseled and instructed to eat a standard 55% carbohydrate, 15% protein, and 30% fat diet. After a 12 hour fast, on the test day they consumed either a high GI corn flake cereal meal, or a low GI FiberOne cereal meal with water, within 10 minutes (Yum! LOL). The GI of the response was directly measured compared to a 50g oral glucose load, and cereal serving size was standardized to provide 50g available carb (aka net carbs in LC circles). Below are the plots of the results from this study.
|GI Index compared to 50g glucose. |
High GI is 125, Low GI about 50
|Looks like a significantly |
nastier glucose spike to me!
|The insulin behavior tracks the glucose response, predictably. |
The low GI carb barely suppresses leptin in the 2 hours after eating.
|The total insulin response for Low GI carb is roughly half that of High GI,|
The relative leptin responses?
Following the High GI meal, total leptin is roughly 1/3rd that following the Low GI meal.
What we have here folks is what a certain former amateur boxer might call a one-two punch. Punch 1: The leptin and insulin responses to differing GI meals do not correlate, rather they are in opposition. Punch 2: Rather than spiking leptin, carbohydrate suppresses it in the immediate postprandial phase. Carbohydrates, if anything, "unspike" leptin. What cannot be reconciled here is this whole notion that insulin resistance and leptin resistance, caused by spiking insulin and leptin levels, go hand in hand with carb consumption. It's plain as day that the in the postprandial state, the effect is, if anything, reciprocal. Blood glucose suppresses leptin in living intact human beings.
As usual, I have some thoughts flying around in my head about now on the ramifications of the results seen here. I have to put them together with some info I've been reading on high fat meals and postprandial leptin levels. Perhaps the mixed meal is striking again as an issue here. That is (and it remains to be seen) if diet has any significant effect on long term, "global" if you will, leptin levels and signalling.
Damn those "inconvenient facts" eh, Ron? I would suggest that rather than trying to put me down by making ridiculous statements about how I don't know the science, Rosedale should do some scientific damage control in his scripture. Somehow I doubt he'll heed my advice. Meanwhile over in the "we're all gonna die from ..." Mercola-land, not only are we warned of the dangers of two natural foods (potatoes and rice will whack the mole outta your blood glucose!!!!!!), but his readers have been warned about reading my posts. Yep ... I've earned a "Dissenter Badge" there. Wow! That's a badge I wear with honor:
CarbSane has a Dissenter BadgePlease be aware that this user has posted comments that are in serious disagreement with Dr. Mercola's position and their comments should be viewed with caution.You've been warned here first. Meanwhile, at least Mercola hasn't censored me (yet). I'll get to Ron's issues with scientific debate soon. Have a great night folks!
Make my next leptinade ultra-virgin please!