In a multi-cat household, it's not uncommon for your cats to require different diets. As the lifestyle, health, and condition of each cat varies, so does the amount and type of food they should receive.
For example, an older cat may benefit from a senior diet that has high protein levels to maintain lean body mass. On the other hand, an overweight cat may be better suited toward a weight-management diet that still provides the nutrients she will need, while having fewer calories than a standard formula.
If your cats are already familiar with eating from different bowls, no training will be necessary. However, if your cats are now being introduced to the idea of eating separate food, some training will be required in order for them to adjust.
Separating your cats and their bowls during meals will help accustom the cats to the idea of eating different food from separate bowls. Be sure to keep an eye on your cats when introducing this idea, as they may want to stray and try one another's food. However, after time, your cats should adjust and will eat their own food as routine.