Adjust this daily to meet the demand. In addition, add variety by giving little bits of fruits and veggies every day. Don't go too heavy on the people food or greasy, salty, or sugary treats, no matter how much the little boogers beg. In general, adult rats need lower levels of protien and fat than do baby rats. This is because they are finished growing.
Further adjustments have to be made for the elderly rat.
I will give details of how I handle nutritional needs of each population below. Grain mix for rodents can be substituted for some of the lab block allotment. Rats like most fresh or frozen fruits or veggies. This is by no means a complete list. Also I give my girls wheels to run on, which they are much more likely to use than the boys ever would be, and the runners seem to need the extra richness in their diet to keep their weight at a healthy level.