Fasted cardio study

[url]http://m.jp.physoc.org/content/588/21/4289.full[/url]

I thought this one was very interesting. It seems like a well designed study looking at the effects of fasted cardio. Although their primary focus was insulin sensitivity improvements (which were impressively greater with fasted cardio), they measured body composition too (body weight + calipers).

So three groups: one control, one doing fasted cardio, and one doing fed cardio. All subjects were at a hefty 30% caloric surplus (from baseline) with a high fat, moderate carb, moderate (to low) protein diet (typical for endurance training). The control group got fat, the fed cardio group got less fat, and the fasted cardio group didn't get fat.

[quote]
[b]in CON, body weight on average increased by ~3 kg[/b] (range +0.4 to +5.7 kg) from the pretest to the posttest. This weight gain was largely, if not entirely, accounted for by fat accretion as evidenced by the 15% increase in sum of skinfolds, reflecting elevated subcutaneous fat deposit. Changes in body weight and sum of skinfolds were also highly positively correlated (R = 0.84; P < 0.001). [b]This increase in body weight and skinfolds was largely negated by training in F[/b] (P < 0.05). Thus, compared with the pretest, neither body weight (P = 0.13) nor sum of skinfolds (P = 0.75) was significantly increased in the posttest. [b]Conversely, in CHO, body weight on average was increased by ∼1.5 kg[/b] (range −0.2 to +2.6 kg, P < 0.05), which was less than in CON (P < 0.05)
[/quote]

I think this one is so interesting because unlike nearly all other work done on fasted cardio, this one is done in the context of induced insulin resistance through overfeeding. It seems as though fasted cardio (more so than fed cardio) might be protective against insulin resistance from overfeeding.

I think this is way less applicable to people in a deficit, who probably wouldn't see a damn bit of difference from fasted vs fed cardio (as we've seen in other studies), but I wonder if there's a practical application here for guys on a bulk. Are there improvements in nutrient partitioning to be had?

The argument against that though is that adding cardio of any kind [b]on top of lifting[/b] may not lead to further improvements in insulin sensitivity (you can only improve so much).