If I am not mistaken, that was a popular diet plan, Atkins?, until a few months ago, eat all the protein you want and cut out the carbs. Didn�t work for people, but who knows with fish.
Some tilapia are being breed to be kinder, gentler fish, so that they are easier to handle at harvest. Also, stripped bass were fed diets containing fish oil and were able to live and breed in northern climates. So maybe diet alone is not an answer, need to add in genetics as well if you want big fish that bite..
I do know that immediately after feeding my fish, they are easier to catch, I know these fish are not �full�, they certainly are fat. I think they are not unlike the double breasted cormorant, they will only stop eating to rest.

1/4 & 3/4 acre ponds. A thousand miles from no where and there is no place I want to be...
Dwight Yoakam