Do you need carbs for exercising?
What about carb timing? Is it necessary if you are fat adapted?
What about the intensity and duration?
Are you fat adapted, metabolically efficient and flexible?
Are you burning higher percentage of fat at higher intensities?
Are you burning some carbs but sparing muscle glycogen …leaving you back up fuel for the sprint finish or Time Trial home?
How do you fuel for a high intensity training session or a long endurance workout at MAF?
It depends.
Here is one article to review… https://www.ditchthecarbs.com/how-to-be-a-ketogenic-athlete/
LOWER INTENSITY endurance activity INCREASES ketone levels
If you’re on a ketogenic diet and you start exercising at a low to moderate intensity, your blood ketone levels will increase and your blood glucose levels will decrease.
This is because you’re demanding even more fat from your fat stores to fuel your activity, some of this fat gets turned into ketones.
That happens when you rely on large enough amounts of fat. Indeed, elite endurance runners eating a ketogenic diet burned 2.3 times more fat than their high-carb counterparts during the peak fat burning stage [2].
HIGH-INTENSITY activity momentarily DECREASES ketone levels
Say you ramp up the intensity to around 75% or more, what then? Your ketone levels will drop and your blood sugar will increase. This is normal and temporary.
You’re demanding more energy from your body at a faster rate, and since glucose ‘burns faster’ than fat, you start using a higher proportion of fuel from glucose. Although you rely proportionally less on fat at high intensities, you’re still be burning more fat overall because your total energy needs went up.”