I don't often get a flashback to middle-school -- those were NOT the happiest years of my life! But ruminating on the better aspects of burning-carbs-with-exercise last week, i pulled up two memories of the old days....
Which classroom gave us our first contact with the subject of logic? I'm not sure; it had to have been either English or science. And, or, if, then: that was the sort of thing my geeky mind found entertaining! (It wasn't until my last year of high school that i discovered algebra could be as fun as working puzzles -- up to then math had just been drudgery.)
SO! IF you're doing a lot of physical work like hauling weights up an 8% grade, THEN you can afford to eat more readily-burned fuel like starches. IF you are not doing such work AND you eat the starches anyway, THEN you will either gain fat weight OR burn the excess calories as heat, but the latter only IF your metabolism is "whole" enough to do that sort of thing.
I could go on like this forever. Central point is, all your hormonal and metabolic ducks have GOT to be in a row to be able to pull off the starch-eating. Most of the time, mine are not.
The other connection from the "bad old days" is just an object-lesson: when i ceased riding the bus the 1.1 mi distance to school and began walking it twice a day, the "seal-puppy" i once was lost quite a bit of fat and got significantly more fit. An adolescent's hormones can be just as F'd up as a middle-aged woman's, i suspect! This SHOULD nudge me to do my 2 miles a day ... but will it? ..."Earth to Tess...?!" [crackle of "dead air"]