Kardio på tom mage/fastende mage unødvendig

Dette er vel det mest vanlige tipset for å øke fettforbrenningen, og omtrent "alle" byggere og fitnessutøvere kjører kardio på tom mage. Dette er basert på at mat øker insulinutskillelsen, og dette setter en brems på fettmobilisering og forbrenning.

Denne studien viser imidlertid at selv inntak på opptil 150g karbohydrat (!) før to timer morgenkardio ikke reduserte fettforbrenningen sammenlignet med fastende kardio. Dette bekrefter bare det jeg "maser" om i artikler og på forumet, det er totalt kaloriforbruk i forhold til kaloriinntak på slutten av dagen som er mest avgjørende - ikke hvilket drivstoff du forbruker under selve treninga.

For de som er veldig lavt i fettprosent vil det med spesielle sekvenser av intervaller og moderat-intensitetskardio kunne være en fordel å kjøre det på fastende mage, men dette hører med til unntakene. Du kan finne ut mer om dette i boka Stubborn Fat Solution av Lyle McDonald. Konklusjonen er at du heller skal gjøre kardio når det passer deg best, og en morgentur før frokost er helt klart en fin start på dagen men ikke noe du skal tvinge deg selv til.

J Appl Physiol. 2008 Apr;104(4):1045-55.

Effect of training in the fasted state on metabolic responses during exercise with carbohydrate intake.

De Bock K, Derave W, Eijnde BO, Hesselink MK, Koninckx E, Rose AJ, Schrauwen P, Bonen A, Richter EA, Hespel P.

Research Center for Exercise and Health, F.A.B.E.R. - K.U.Leuven, Tervuursevest 101, B-3001 Leuven Heverlee, Belgium.

Skeletal muscle gene response to exercise depends on nutritional status during and after exercise, but it is unknown whether muscle adaptations to endurance training are affected by nutritional status during training sessions. Therefore, this study investigated the effect of an endurance training program (6 wk, 3 day/wk, 1-2 h, 75% of peak Vo(2)) in moderately active males. They trained in the fasted (F; n = 10) or carbohydrate-fed state (CHO; n = 10) while receiving a standardized diet [65 percent of total energy intake (En) from carbohydrates, 20%En fat, 15%En protein]. Before and after the training period, substrate use during a 2-h exercise bout was determined. During these experimental sessions, all subjects were in a fed condition and received extra carbohydrates (1 g.kg body wt(-1) .h(-1)). Peak Vo(2) (+7%), succinate dehydrogenase activity, GLUT4, and hexokinase II content were similarly increased between F and CHO. Fatty acid binding protein (FABPm) content increased significantly in F (P = 0.007). Intramyocellular triglyceride content (IMCL) remained unchanged in both groups. After training, pre-exercise glycogen content was higher in CHO (545 +/- 19 mmol/kg dry wt; P = 0.02), but not in F (434 +/- 32 mmol/kg dry wt; P = 0.23). For a given initial glycogen content, F blunted exercise-induced glycogen breakdown when compared with CHO (P = 0.04). Neither IMCL breakdown (P = 0.23) nor fat oxidation rates during exercise were altered by training. Thus short-term training elicits similar adaptations in peak Vo(2) whether carried out in the fasted or carbohydrate-fed state. Although there was a decrease in exercise-induced glycogen breakdown and an increase in proteins involved in fat handling after fasting training, fat oxidation during exercise with carbohydrate intake was not changed.

Børge A. Fagerli

Daglig Leder og MyRevolution Coach

borge@myorevolution.com