There is so much in that study. Some of my takeaways:
- the study suggests that feeding CHO does not spare muscle glycogen whereas in the end mentioning other studies that contradict that point. So still some confusion on that aspect
- Feeding CHO does not flip a switch putting you into a stop using fat mode. In fact the picture above shows still big amount of energy used from fat even when fed CHO.
- So even if higher fat oxidation rate when restricting CHO…if taking CHO you’d be able to go longer and so overcompensate overall fat utilized.
- On the other hand…(and that supports the point you made):
- But (for the bigger difference) note “from 80 min of exercise to fatigue”… that’s long into a hard exercise (I can’t imagine 70% VO2max for 3-4 hours (citing:“slightly below subjects’ blood lactate threshold”)
) … so it becomes a balancing act if you go down that path and need to keep upcoming training in mind…
What I ask myself:
- But I don’t even know if one can conclude that let’s say having 10-20% higher fat utilization during some part of a workout effectively results in a permanent change of how your body uses fat for energy (or how many of these sessions would be needed for some permanent effective change)?
- If so…what would be needed to permanently keep that changed physiology? Or would then taking more CHO again reverse that change?
- Is it even sure that having let’s say 20% higher fat utilization during some part of a workout effectively trains the body to use fat better than a CHO fed workout with still good (but just not as high) fat use?
Any input welcome!