Crossfit and Body Building after VSG

I'm am over eater which had led me to an unhealthy weight. I love lifting weights and Crossfit. Does any one have any information on how long before I can start exercise that is like Crossfit or heavy lifting. I have had incidents in the gym where I haven't consumed enough calories and I feel like I will faint. This has happened when I have been on diets desperately trying to lose weight. Does anyone feel faint or weak when exercising because of the new smaller stomach. Please let me know thank you.

You won't be able to do anything but walk for 6 weeks. Then you can slowly ramp up on activity.

I've never felt weak/faint when I go to the gym. I tend to work out fasted and eat afterward. The only difference is long runs (over an hour) and then I'll use a single Clif Blok every 30 minutes or so. And I always hydrate.