There’s no should or shouldn’t with fasted training. What you need to think about is what your overall goals are, and the type of training you’re doing.
Fasted training has really grown in popularity over the last few years, and why not when the benefits include increased insulin sensitivity and increased levels of Human Growth Hormone (HGH), not to mention great weight loss…
But, and there is a but, this can come at a cost… Namely increased cortisol levels. Stress hormone cortisol will rise when we train anyway, but resistance training is glycogen intensive and if we’re fasted we’ll produce more cortisol (bad) to break down amino acids in the muscles (bad) so the body can produce it’s own energy.
What this means in simple terms is that if we deplete our glycogen reserves we’ll start breaking down muscle for energy, which is not what we want.
Cardio and HIIT on the other hand rely on glucose for fuel, and also utilise body fat for fuel, so while cortisol will still increase, it won’t be to the same extent as resistance training, as long as you keep your session short.
The other element you need to consider is when and what to fuel with around these workouts, again this will depend on your overall goal and type of training, I won’t dive into that here, but it’s important.
Bottom line, train in a way that reflects your goals and know what you’re doing.
Want to lose mass of any kind, fasted everything (note you really don’t want to do this because of the loss of muscle and the metabolic knock on from losing it).
Want to preserve or gain muscle, fuelled resistance.
Want to burn fat, short fasted HIIT or cardio.
However in between these options there are various strategies you might want to consider to get best results for you and other ways you can hack fat loss…
For example, finisher sequences after resistance, separate HIIT and resistance days, combining HIIT, resistance and fuelling strategies…
Simple, Not simple. If you want to know more give me a shout.