I went paleo last year when I was 236 lbs at 5'9'' as a female, size 14 pants and xxl shirts. I lost 63 lbs and went down to 173, a loose size 8 pant and medium shirts with about 25 lbs left to go as a goal. I thought why not do a fat fast and in a week, I lost 14 lbs. I was feeling great until one night I had a massive panic attack for the very first time in my life at 25. I couldn't breath and I had to be rushed to the hospital. They injected me with lorazapem and told me that my diet led to this episode. I did test a little bit low on potassium but otherwise I was fine. When I was released, I didn't want to worry about food so I ate paleo, but a higher carb paleo and I rapidly began to gain weight. I don't know if its real weight however because I still fit in medium and 8, I just look a bit more bloated at 185ish so maybe its just water weight? Anyway I'm fine most of the time until I begin to go lower carb to lose again. This is the only way that my appetite is suppressed and I don't go overboard and the only way I really begin to see results. I also take supplements now to prevent becoming deficient in anything but each time I attempt to go back to low carb I begin having horrible panic attacks (can't breath, feel nauseous, like i will faint, palpitations, irrational obsessive fear). Why is this happening? I'm taking supplements, getting enough fat in my diet, enough sleep, drinking broth, keeping positive, i didn't eat junk so I'm not detoxing from grains or refined sugar. Am I just not meant to be low carb anymore? Should I just eat moderate carb and fat paleo with lower calories and wait to get to my ideal weight in a longer time? I really need help. When I talk to my doctor he tries to discourage paleo completely and recommends a low fat high carb and high fiber diet that made me fat to begin with during my vegan days!!!
There are several things you could try to get adapted to burning fat instead of carbs - your mitochondria have to remember how to do that, and your cells need to see the new source of energy.
Try consuming coconut oil or MCT oil (you can put it in coffee for example.) It will provide a ready source of ketones. Start very slowly with this - say a teaspoon and work your way to a tablespoon a day; try to drop the carbs when you do consume MCT/coconut gradually.
Alpha Lipoic Acid can help with the adaptation.
L-Glutamine is an amino acid that can cross the blood-brain barrier and can be used as a source of energy and it quiets down cravings for carbs.
Make sure you're consuming enough meat as well. Calculate your lean body mass in pounds, multiply that by 0.8-1, then if it's chicken, multiply by 3, if it's something like beef, multiply by 4 to get how many grams of meat you need to eat. Or eat 3 palm sized portions a day.
It does sound like your body is used to a higher glucose level, and when it drops too far below that, it thinks you'll crash, so it signals cortisol, which sadly causes your panic attack, but it also does signal gluconeogenesis, which if you don't have enough spare protein from food, will cause muscle catabolism.
You should avoid doing very low carb and fasting at the same time, that will lead to this very issue.
Edit: just got this via email, might help: