My days were a lot less productive when I ate a lot of carbs. I spent about half the day sleepy or starving, unable to really think at those times.
OFC when you eat 1000 cal meals you are going to have a huge sugar drop doesn't matter if it's a huge steak or whole cake. People also waste too much time on controlling caloric intake over way too short periods if you can't control you weekday intake to the required levels just lay down on it during the weekend and you'll still be fine.
All these diet's are really a waste of time and money, eat on a regular schedule (never eat when you are starving, as in never get to the point of feeling real hunger), have a diverse diet, try to expand your meals to as many a day as possible, heck I've seen people losing pounds in a heart beat by doing things as simple as droping 1 item from their lunch or moving it to an afternoon snack...
Not to mention that people don't tend to eat the leanest cut available so all of those T-Bones and Rib-Eye's add a huge chunk of saturated fat into the mix and that's without all the addons like that nice sour cream and peppercorn sauce with those nice roasted potatos....
Consuming large portions of meat will increase your BG level's they won't spike as fast as if you would chuck down a bowl of ice cream but they'll rise quite well and crash just as quickly later...