Do you think it would be a good change if when eating food that gives more FEPs that the bar can hold then it would be applied to new bar instead of being wasted completely? To balance it out there could be some percentage deducted per every fill, perhaps up to half of the overflow.
Example: fresh spawn eats 100 FEP food (after the ravenous bonus) it would gain one attribute increase and have half of the overflow (90/2=45) left that would give second attribute increase leaving (34/2=16) enough for another third increase and (4/2=2) points to fill the bar.