Back in this post I discussed the study by Knudsen et al on forced overfeeding. It found, very clearly, that acute overfeeding produces acute fasting hyperinsulinaemia, provided you feed utter crap.
The hyperinsulinaemia moderates progressively over the next two weeks, at which time the study ended.
In comments after the post this one came up from Dr Guyenet:
"You are utterly confused Peter. These people only gained 0.8 kg of fat mass. Over the course of the study, they went from lean to slightly less lean. If you look at studies where overfeeding produced greater fat gains, you see a consistent increase in fasting insulin that corresponds with fat gain, just as those silly obesity researchers would predict:
www.ncbi.nlm.nih.gov/pubmed/18171910
www.ncbi.nlm.nih.gov/pubmed/20814413
www.ncbi.nlm.nih.gov/pubmed/21127472
In animal models of diet-induced obesity (rodents and dogs), blocking the hyperinsulinemia has no effect on the rate of fat gain. The carbohydrate-insulin-obesity hypothesis is dead and buried, and all that remains are rearguard attempts to salvage it using increasingly complex theories. Just let go of the cognitive dissonance man."
with those three studies to back up the comment.
So, being a bit of a dissonant pedant, I checked the studies for information on changes in fasting insulin with time. Here they are, with Knudsen's data at the top:
nm stands for not measured.
As you can see 18171910 covers none of the acute changes in insulin levels discussed in the post. I've spent a great deal of time discussing adipocyte distension induced insulin resistance and this will be the end effect of sustained adipocyte distension. It will kick in eventually and certainly affects fasting insulin levels.
The second study clearly shows on day 14 and day 28 EXACTLY the same changes seen by Knudsen et al in their 14 day study. Anyone want to how high fasting insulin peaked on day 3 in 20814413? Not measured, but answers on a postcard to... Hint, probably very high.
The third study measured, but doesn't report, fasting insulin only at > day 56 of overfeeding. Oh, and day 0 of course.
These are the classic half truths so typical of modern obesity research, technically correct but comprehending nothing.
But here's the real giggle, again quoting the Good Doctor:
"These people only gained 0.8 kg of fat mass"
These people gained 1.5kg of fat mass. From 10.5kg to 12.0kg. The drop to 11.29kg of fat mass occurred AFTER the overfeeding had finished.
I don't suppose reading the studies matters that much in obesity research.
Personally, I'd be embarrassed to be Dr Guyenet.
Peter, as confused as always.
