I'm no expert, but I wanted to caution all of those who are coming here fresh from Kimkins.
If you have been eating really low fat for the past several weeks to months, (the longer you've been low-fat, then the more careful you should be)
PLEASE add your fats and oils back into your diet VERY VERY slowly.
Your gallbladder may have been "on vacation" and in some cases (particularly in those with high serum cholesterol) can develop sludge. This sludge will be in the way when your gallbladder is activated by dietary fat, and can cause severe pain!
One of my first scares on Kimkins was the 2-3 days when I began to transition off the ultra low fat by adding butter and cream. I was in terrible pain for several days.
Reference Dr. Groves
Transition Slowly - Weston A Price site