Thursday, September 23, 2010

Cardio on Empty Improves Insulin Sensitivity

Doing your cardio sessions on an empty stomach (mostly first thing in the morning) may be debatable, if you are already lean and eat a clean and healthy calorie-restriced diet. If you gorge yourself of fatty high-energy foods, on the other hand, you may be happy to hear that K. Van Proeyen et al. (Proeyen. 2010) found "fasted training is more potent than fed training to facilitate adaptations in muscle and to improve whole-body glucose tolerance and insulin sensitivity during hyper-caloric fat-rich diet".

The scientists had a group of healthy male volunteers (18-25y) consume a hyper-caloric (~+30% kcal/day) fat-rich (50% of kcal) diet for 6 weeks. Part of the subjects performed endurance exercise training (4d/week) in the fasted state (F; n=10), whilst the others ingested carbohydrates before and during the training sessions (CHO; n=10). With regard to the effects of this intervention the scientists write: 
Body weight increased in CON (+3.0±0.8 kg) and CHO (+1.4±0.4 kg) (P<0.01), but not in F (+0.7±0.4 kg, P=0.13). Compared with CON, F but not CHO enhanced whole-body glucose tolerance and Matsuda insulin sensitivity index (P<0.05). Muscle GLUT4 protein content was increased in F (+28%) compared with both CHO (P=0.05) and CON (P<0.05). Furthermore, only training in F elevated AMP-activated protein kinase α phosphorylation (+25%) as well as up-regulated fatty acid translocase/CD36 and carnitine palmitoyltransferase 1 mRNA levels compared with CON (~+30%, P<0.05).
 So, you can (almost, cf. table 1) prevent weight gain from bad diet habits by fasted state training,
Table 1: Effect of high-fat diet, alone or in conjunction with training in either the fasted
or the carbohydrate-fed state, on body weight and subcutaneous fat.
you can enhance glucose tolerance and c) you can jack up AMP-K and improve fatty acid oxidation. What are you waiting for? Get out of bed and run! If you can't drag your ass out of bed without it, pop a stimulant fat-burner, like VPX Meltdown or OxyElite, they will help to further increase fat-loss, as well.