I'd just like to encourage people to experiment with carb levels rather than give up too quickly if they find that induction level carbs don't agree with them. Dr. Atkins in his book says you shouldn't suffer and if you experience bad symptoms, then raise the carbs a bit. I think this has to be particularly relevant to anyone experiencing a full-blown chronic illness, because any strain on the body will be more acutely experienced. I recommend Dr. Atkins' book to anyone who is trying a low-carb diet. It is full of wisdom and the experience borne of years of running a successful weight-loss clinic.

I've never experienced "induction flu", possibly because I have never been a great consumer of refined carbohydrates.. However, I have noticed that my carb needs can fluctuate. Although I normally feel far better on ultra-strict Atkins induction level carbs, I have hit at least one period when physically I experienced symptoms like those described by the original poster.. Glued to the bed, leaden bodied, practically passing out if I tried to do anything. Generally increasing my carbs by measures like adding about 2 tablespoonfuls of pulses daily to my diet completely "did the trick", and acted like medicine for that period. After several months, I was able to go back to induction level carbs. I still cannot account for it, other than perhaps as my weight had gone down, my carb needs increased, possibly because I got cold more easily without the extra layer of fat, and for some reason, my body didn't feel inclined to burn any more fat.

Some people do have higher carb needs than others, and I personally have always had to experiment to see which ratio of fat, protein and carb suits me best at that particular time.