Came across this while researching LC effects upon IGF-1, as I'm curious if lower blood-levels of IGF-1 from LC diet might offset the tendency of dairy to raise IGF-1 blood levels, which might then increase risk of certain cancers.

Anyway this study showed that in only one week a LC diet built muscle without exercise! Even before being LC adapted.

http://www.ergo-log.com/lowcarbwithouttraining.html

Interesting, my guess is that the subjects consumed higher protein ( grams per day ) on the lower carb diet so this is where the increased muscle comes from.

Ofcourse lets not forget that there is an upper limit to how much muscle you can gain from eating higher protein. Bodybuilders are obsessed with eating tons of protein I know

Wait... they show muscle growth and they talk about muscle loss on low carb? Biased much?

This was definitely a high-protein low carb diet at 35% of calories from protein. The people were eating 10% protein before? Maybe they were protein starved.

That's interesting. Serum IGF-1 goes down while the muscle cells start producing more of their own IGF-1.

The analysis from ergo-log is missing a critical aspect - hormone receptors. When you cut carbs, it's true that insulin goes down, and it's true that insulin is an anabolic hormone, but it's also true that insulin sensitivity goes up, therefore more than compensates for the drop in insulin. Whoever wrote that analysis should know about that if I understand the goal of that website. To illustrate, growth hormone and its receptor. Women produce tons more growth hormone resulting in a much higher basal level than men, but men have tons more GH receptors thereby making GH that much more anabolic for men when it is released in pulses especially during sleep. This particular detail is common knowledge in bodybuilding. There's also the affinity for IGF-1 from the liver to plug into the insulin receptor. If there's less insulin, then IGF-1 from the liver becomes that much more anabolic by virtue of having a greater chance of plugging in the insulin receptor, which have also increased in number. But then if cells outside the liver can produce their own IGF-1, liver IGF-1 is less relevant for growth of those cells.

But the world of bodybuilding still believes in carb-loading for all kinds of reasons. Then there's the starting diet of those subjects - 10% protein. I don't know how much absolute protein, but even in low-carb studies that compare low-fat diets, 10% protein is unusual. 20% protein seems to be the norm across all diets. If 20% is the norm, then for a 2,000 kcals diet, 10% is half or only 50g/day of protein. It's obviously not enough. The test diet contained 35% protein, so for a 2,000 kcals diet, that means 175g/day. That's 3.5x the protein in the starting diet. So that might be a significant factor as well. But low-carbers don't eat 35% protein, they eat 20% protein. I'd like to see that diet tested instead. Still, there's something to learn here. It seems to refute the idea that protein interferes with fat loss. It might mean if weight goes down when you cut protein, then maybe it's because muscle tissue is being lost.