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Do carbs “spike” leptin?

This seems to be a central tenet to Dr. Rosedale’s science, but it appears to be false according to Carbsane.

Is there any more evidence either way that anybody wants to share?

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Isn't what Rosedale cares about is that he thinks that this spike leads to overall higher levels of leptin? BTW if anyone wants it, I have a spreadsheet of cross-cultural fasting leptin values. It has Tanzanian horiculturalists, low-carbers, Rosedale's study, Siberian Buryat pastoralists, and Kitavans so far. I haven't gotten around to converting the data to be the same metric units because I'm been so busy though. – Bread-Eating Beelzebub Nov 29 2011 at 17:14
Evelyn noted that Rosedale is not concerned that the spike leads to higher levels of leptin per se, but that he argues that these spikes cause leptin resistance, thus breaking its role in moderating our appetite. If there are no spikes, that certainly hurts his argument. – Beth-WeightMaven Nov 29 2011 at 18:15

4 Answers

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Yes, carbs raise leptin, but not in a "spiky" fashion.

Edited to answer Evelyn:

I think it is important to differentiate postprandial effects from chronic effects, ie. which show alteration of its pulsatile/circadian secretion. For instance:

High glycemic index carbohydrate diet alters the diurnal rhythm of leptin but not insulin concentrations

(...) the high GI CHO diets, A and C, altered the 24-hr leptin profiles. Serum leptin rose >above the 0800 hr baseline as early as 1300 hr, whereas leptin concentrations with diets B and D did not rise above baseline until 2400 hr. The leptin AUCs from 1230 hr to 2400 hr for diets A and C were significantly higher than for diets B and D (P < 0.0001) using the first model.

The 24-hr AUCs for leptin on diets A and C were significantly greater than the AUCs for leptin on diet B (P < 0.003) using the second model. Meals indicated as solid arrows, open arrows equal snacks.

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From Postprandial leptin response to carbohydrate and fat meals in obese women.

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You can see that approximately at the 3 hour mark, leptin concentrations start to rise in both normal and obese women. So there seems to be an steady increase, not a spike, but an increase in the end, which was correlated to carbohydrate but not fat (note the concentration of leptin in obese and lean in the picture above):

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In the study you cite (A High Glycemic Meal Suppresses the Postprandial Leptin Response in Normal Healthy Adults), they measured the leptin response 120min after, and as we have seen, the increases seem to start 2-3 hours later.

I havent researched much, but from what I remember, glucose stimulates leptin expression. The immediate postprandial rise in insulin and BG following a carbohydrate rich meal, would stimulate secretion of leptin, which would show higher levels more delayed than the insulin/glucose response or a different pattern of peaking, like seen in the first study cited.

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 Did you see the previous post Lucas? carbsanity.blogspot.com/2011/11/… The "carbier" carb (high glycemic) suppressed leptin moreso than the low glycemic carb. Things that make you go hmmmm – Evelyn aka CarbSane Nov 29 2011 at 15:42
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 Plus one Lucas........ – The Quilt Nov 29 2011 at 16:22
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 Lucas, from the first study above: Although the 24-hr glucose and insulin profiles did not differ with the diets, diets A and C altered the serum leptin diurnal pattern. ... These results suggest that the pattern and amount of leptin secretion may be altered by high GI CHO or the simple sugar content of the diet, unrelated to differences in insulin concentration, that high GI foods may have little or no effect on serum insulin in the context of a mixed meal, and that a single 0800-hr leptin value may not be sufficient to reveal a diet-induced change in leptin secretion. – Evelyn aka CarbSane Nov 30 2011 at 12:23
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 Rosedale's premise is that BG spikes → insulin spikes → insulin resistance, and BG spikes → leptin spikes → leptin resistance. He bases his premise on in vitro studies showing glucose & insulin stimulate leptin release. Your study is yet another one demonstrating that this is NOT seen in vivo. – Evelyn aka CarbSane Nov 30 2011 at 12:27
Evelyn, I am not supporting Rosedale's hypothesis, as shown by the studies above, but they show that it is possible that a high GI cho diet affects 24h leptin, for whatever the reason is. – Lucas Tafur Nov 30 2011 at 12:56
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For those who don't follow my blog, you might be interested in this post: http://carbsanity.blogspot.com/2011/10/24-hour-leptin-profiles-sleep-off-your.html

There is a sampling of 24 hour leptin level profiles there.

Does what you eat (and when you eat it) influence leptin levels? Seems so. But not in what is traditionally understood to be a postprandial spike. Indeed what is influenced is the diurnal (turns out middle of the night) rise in leptin.

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 Again with the down votes. I'm seeing a pattern here ;-) – Evelyn aka CarbSane Nov 29 2011 at 16:47
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 Someone downvoted the question itself too, so maybe it is just the leptin-haters......or The Quilt... – Paleo2.0 Nov 29 2011 at 17:05
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 yes, carbsane, there is a pattern – The Loon Nov 29 2011 at 18:10
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 No worries, I'll upvote it all then! – raydawg Nov 29 2011 at 18:57
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Funny how nobody talked about leptin before The Quilt popularized/polarized it.

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 I think Stephan and Peter and ItstheWoo were talking about it long before I ever heard of The Quilt. – Paleo2.0 Nov 29 2011 at 15:55
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 No one tied it to the diurnal circadian cycle and talked about how to use it clinically in neuroplastic repair of the leptin receptor. I spoke about the sexual dimorphisms of leptin and its circadian cycle in my podcast earlier this month with joanneunleashed.com. Who said what first is not material. That it is part of the discussion is very material. – The Quilt Nov 29 2011 at 16:27
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 Rosedale has been talking about leptin for years. The only reason it is in the news more is because he has been commenting more on it now that he has more time, and recently started a blog, so of course, carbsane had to go after him to complete the set. – The Loon Nov 29 2011 at 18:10
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 The only reason leptin is in the news more is because Rosedale has more time and now a blog? Yeah, I'm sure that's it. Me, I'm glad CS has the time & energy to dig into this. – Beth-WeightMaven Nov 29 2011 at 18:23
I meant the "rosedale-leptin" topic, not just leptin itself. The original question is about Rosedale's theory. – The Loon Nov 30 2011 at 15:33
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I posted these in the comments on her blog yesterday

http://www.ncbi.nlm.nih.gov/pubmed/9084976

This pronounced fall in serum leptin in asso- ciation with reduced carbohydrate intake before sub- stantial loss of body fat suggests a role for leptin in defending the body’s carbohydrate stores and impli- cates leptin in the satiating effects of carbohydrate.

http://ajpendo.physiology.org/content/277/5/E855

In conclusion, the results of the present study demonstrated that a carbohydrate meal induces a greater postprandial leptin response than an isoenergetic fat meal and that this response is correlated to the physiological postprandial insulin response.

Her reply was that

Your second study is actually the one I blogged on previously from which the first graphic in this post came. I wouldn't call the delayed rise in leptin levels a "spike" by any stretch of the imagination. The other study discusses leptin levels going down with carb restriction. Given that this occurs in fasting, and many features of fasting/starvation are thought to be linked to glycogen depletion/glucose availability, this is no surprise.

I tend to agree with her in spite of the authors' findings. I am going to keep looking into this....

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Just to clarify, your comment is here: carbsanity.blogspot.com/2011/11/… ... I was referring to this study you linked to ncbi.nlm.nih.gov/pubmed/9084976 with the comment you quoted above. The study in this answer is actually the one from which the graphic in that post you commented on came from. Note the timeline: 9 hours. That's like having breakfast at 6am and saying my leptin "spikes" in the afternoon because it finally drifted up past baseline. – Evelyn aka CarbSane Nov 29 2011 at 15:23
yeah, thanks. I initially flip-flopped the links. But I think I've got it straight now. And yeah I agree with you, I'm still trying to see how they got their conclusions. – Jeff Nov 29 2011 at 15:30
Did you see the test diet meal in that second study? 90g of strawberry jam, 90g of maltose solution and 500g of fat free cottage cheese. What a bizarre meal. – Matt Nov 29 2011 at 15:33
The authors are using the AUC's and clearly -- moreso in women -- leptin levels do rise following the carb meal. However it is quite delayed. If a second and third meal were consumed, I think leptin would likely stay low. This is what the 24 hour profiles I linked to in my answer seem to show. – Evelyn aka CarbSane Nov 29 2011 at 15:38
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 I far prefer Todd Becker's hypothesis to Rosedale's! Todd theorizes that leptin resistance is related to high triglyceride levels interrupting leptin transport at the blood brain barrier. If true, this could explain why LCing works as a weight loss strategy. gettingstronger.org/2011/11/… – Beth-WeightMaven Nov 29 2011 at 18:11
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