I don't know...

Eating like this can be a sign of hyperthyroidism, which is pretty common in cats.

I have seen revenge eating...when a new pet is introduced into the family.

The beginning of diabetes also will result in more eating. With time however, they often lose weight in the end until treated.

My son gives his cat a special kidney diet, and she eats twice as much now than before...to make up for the lost protein calories.

If you are giving a "diet" formula, animals may eat more that way. My oldest cat was pretty fat before on Science Diet light.
When I switched her to Eukanuba regular she lost weight!