Now I used to be a huge fan of training fasted (first thing in the morning) when it was all the craze!
“Training fasted will lead to you burning more body fat.”
^^ not totally true ^^
Because we now know in order to lose weight (body fat), we have to ensure we are in a calorie deficit.
So training ‘fasted’ then stuffing your face all day most probably won’t get you the results that you’re after.
This week on my nutrition course the subject was ‘Nutrition For Endurance Sports’ and I’ve learnt something new and very interesting regarding training fasted.
Training fasted has been linked to increases in PGC-1 (alpha) which is involved in mitochondrial biogenesis. So, the more mitochondria we have available the more energy production can occur within the muscle. Training in a fasted state has been shown to improve insulin sensitivity, as well as the body’s ability to continue using fat as a dominant fuel source at lower intensities.
– Van Preen et al. (2010).
According to Fernandez-Marcos & Auwerx (2011), A key factor in determining which fuel source you’re using is the % of your VO2max that you’re working at. Typically, around 65% of VO2max is the limit to where fat is being effectively used as fuel in exercise. Above 85% of VO2max, CHO oxidation limits the fatty acid transport into mitochondria, as CHO becomes the preferred fuel source at higher intensities. HIIT training improves our ability to work at higher intensities because of improvements in CHO oxidation in the mitochondria, useful in sporting situations requiring sustained efforts. However, increasing an athlete’s VO2max as well as their ability to utilise fat as a fuel source at higher rates of VO2max will mean they are able to utilise both fuel sources more effectively.
If you are an endurance athlete that trains first thing in the mornings, it might be worth while training ‘fasted’ for your recovery/slower paced sessions. It may just improve your performance. If you also know your VO2 max, training at around 65% will lead to fat being used as an energy source.
For anything interval based or generally higher in intensity though, defo include a small amount of carbs pre workout (ie. a banana).