Intermittant Fasting in Lean Men

[Steve Shafley]

Lyle McDonald pointed this one out. He postulates:

Insulin sensitivity was improved acutely, probably due to improvements in adiponectin release from fat cells

Full paper:

http://jap.physiology.org/cgi/content/full/99/6/2128

J Appl Physiol. 2005 Dec;99(6):2128-36. Epub 2005 Jul 28. Links
Effect of intermittent fasting and refeeding on insulin action in healthy men.

* Halberg N,
* Henriksen M,
* Soderhamn N,
* Stallknecht B,
* Ploug T,
* Schjerling P,
* Dela F.

Dept. of Muscle Research Centre, The Panum Institute, University of Copenhagen, Denmark. nilsh@mfi.ku.dk

Insulin resistance is currently a major health problem. This may be because of a marked decrease in daily physical activity during recent decades combined with constant food abundance. This lifestyle collides with our genome, which was most likely selected in the late Paleolithic era (50,000-10,000 BC) by criteria that favored survival in an environment characterized by fluctuations between periods of feast and famine. The theory of thrifty genes states that these fluctuations are required for optimal metabolic function. We mimicked the fluctuations in eight healthy young men [25.0 +/- 0.1 yr (mean +/- SE); body mass index: 25.7 +/- 0.4 kg/m(2)] by subjecting them to intermittent fasting every second day for 20 h for 15 days. Euglycemic hyperinsulinemic (40 mU.min(-1).m(-2)) clamps were performed before and after the intervention period. Subjects maintained body weight (86.4 +/- 2.3 kg; coefficient of variation: 0.8 +/- 0.1%). Plasma free fatty acid and beta-hydroxybutyrate concentrations were 347 +/- 18 and 0.06 +/- 0.02 mM, respectively, after overnight fast but increased (P < 0.05) to 423 +/- 86 and 0.10 +/- 0.04 mM after 20-h fasting, confirming that the subjects were fasting. Insulin-mediated whole body glucose uptake rates increased from 6.3 +/- 0.6 to 7.3 +/- 0.3 mg.kg(-1).min(-1) (P = 0.03), and insulin-induced inhibition of adipose tissue lipolysis was more prominent after than before the intervention (P = 0.05). After the 20-h fasting periods, plasma adiponectin was increased compared with the basal levels before and after the intervention (5,922 +/- 991 vs. 3,860 +/- 784 ng/ml, P = 0.02). This experiment is the first in humans to show that intermittent fasting increases insulin-mediated glucose uptake rates, and the findings are compatible with the thrifty gene concept.

[Craig Cooper]

Awesome. I hope this means that there is more research being done on humans to investigate the effects of IF.

[Neal Winkler]

If you want to find more IF studies in humans, you have to look at Ramadan fasting.

[Steve Shafley]

Post a few, Neal.

[Joyce Behrendt]

Some of us type 1 and type 2 diabetics have tried it on the Dr. Bernstein forum after reading Dr. Eade's blog. I'm a type 2, no meds and my morning blood sugars were 95-115 by following low carb and exercising. On the 3rd day of the every other day fast, I hit 84 (normal) and stayed there for a few days until I ate some higher carb foods. I've been fasting about once a week now. It works well for me and reigns in my appetite so I eat smaller portion sizes.

A couple of the type 1's were able to lower their insulin dose.

I saw Robb's name on Dr. Mike's blog about IF and that's what led me here. I'm very interested in it and improving my insulin sensitivity.

If anyone wants to study a chubby type 2 diabetic, I'm in!

[Jonathan Reik]

Originally Posted by Steve Shafley

Insulin-mediated whole body glucose uptake rates increased from 6.3 +/- 0.6 to 7.3 +/- 0.3 mg.kg(-1).min(-1) (P = 0.03), and insulin-induced inhibition of adipose tissue lipolysis was more prominent after than before the intervention (P = 0.05). After the 20-h fasting periods, plasma adiponectin was increased compared with the basal levels before and after the intervention (5,922 +/- 991 vs. 3,860 +/- 784 ng/ml, P = 0.02). This experiment is the first in humans to show that intermittent fasting increases insulin-mediated glucose uptake rates, and the findings are compatible with the thrifty gene concept.

So, IF made it harder to burn fat and made the body more efficient at absorbing glucose? That sounds like a recipe for getting fat(ter). Am I reading that correctly? Or did I misinterpret something?

[Steve Shafley]

Great point to ponder! Here's my go at it.

On an IF, you are completley eliminating insulin excretion after gastric emptying...this occurs, oh, say around 5 hours after a protein/fat meal, maybe quicker. Someone else should know the gastric emptying time of a meal like that off the top of their head. So, overall, you have less time during the day when that matters.

On top of that, insulin does a decent job of shutting down lipolysis. But, since overall you are excreting less insulin, since you are doing an IF and also your insulin sensitivity is improved, you've got to question how much impact that increase in lipolysis has. That "more prominent" (P=0.05) means that the measurement was statistically significant

In addition, this is often said about (P=0.05)

A level frequently quoted is P<0.05. This means that there is a one in twenty chance that the whole thing was accidental

[Jonathan Reik]

Ah, okay... makes sense. Thanks for putting it in perspective.

[Robb Wolf]

Originally Posted by Joyce Behrendt

Some of us type 1 and type 2 diabetics have tried it on the Dr. Bernstein forum after reading Dr. Eade's blog. I'm a type 2, no meds and my morning blood sugars were 95-115 by following low carb and exercising. On the 3rd day of the every other day fast, I hit 84 (normal) and stayed there for a few days until I ate some higher carb foods. I've been fasting about once a week now. It works well for me and reigns in my appetite so I eat smaller portion sizes.

A couple of the type 1's were able to lower their insulin dose.

I saw Robb's name on Dr. Mike's blog about IF and that's what led me here. I'm very interested in it and improving my insulin sensitivity.

If anyone wants to study a chubby type 2 diabetic, I'm in!

Joyce-
Absolutely a pleasure to have you here! Keep tinkering with this stuff, keep us posted on your nutrition and training if you like. We are here to help!