Colder environments, larger cages, free flight cages and breeding activity, does require more energy. But the sedentary life of most cage birds together with the constant availability of food inevitably leads to over eating. This along with the consumption of oilseeds, nuts and other high fat foods limits the eating of other more nutritious foods, which includes formulated diets. Certain higher fat levels should not be considered totally bad. Even eight to twelve percent fat in a formulated diet, is still one fifth the levels found in oilseeds.
Sprouting seeds can reduce the fat levels and add some vitamins.
The problem with sprouting is the risk of fungal contamination such as candida and the space and time needed to prepare the sprouts. The caloric density of a diet is important because this is what determines how much food the bird will ultimately eat. Thus the energy level influences how much vitamins, minerals and protein the bird will receive on a daily basis from the ingested food. More pelleted food needs to be eaten by birds to maintain their weight, in fact almost twice as much as high calorie seed kernels. Fat has more than twice the energy value per gram than protein or carbohydrates and this accounts for the energy differences.