1000 cal workout question


Hi all! I have a 1000 cal workout scheduled this week in the FB fit program (loving the program by the way!!). My question is that I get a bit confused. I read (even commented in the new without released today) that over an hour can / is excessive. I don’t fuel during my workout (or even before it as I do it first thing in the morning). So should I substitute another total body under an hour workout instead? I’m feeling great so far in the program but the workouts are definitely challenging for me! Looking forward to reading your thoughts. Thanks!!