cat is hungry all the time

Female, spayed, 4-year-old indoor, tortoise shell cat named Aurora.

Main problem is that Aurora seems to be hungry more than my other two cats and she has become overweight. Part of the problem was my previous housemate would feed her (often copious amounts of food) to shut her up when I wasn't present, even though I requested she not do this.

With new (conscientious) housemate I have the opportunity to reduce my cat's weight, but I'm not seeing any dramatic change in the months since my former housemate moved, making me concerned my cat may have a metabolic problem.

Aurora has always been an indoor cat, but mother was semi-feral while Aurora was in utero and both were rescued along with Aurora's brother from previous litter. Aurora was birthed indoors, and was the runt of the litter. I am convinced that she did not get much cholestrom when she was nursing. Initially I kept her because she was the most unlikely to be adopted given her problem with nasal discharge.

Is able to go outside and sit on balcony. She gets additional sunlight on weekends and summer evenings by sitting on front steps, but is not allowed to wander. She doesn't seem to like to be in full sun as much as my other cats. On balcony there is a plant she really wants to eat called Elephant Tree (beaucarnia I think). I have to keep her away from it. This is not a problem with the other cats.

Curious, adventurous and generally unafraid, she doesn't seem to be interested in running off when she is outside, though if the neighbor comes out she is not shy and will wander into her apartment to investigate. (I accompany her outside.)

Wandered away from mother frequently after birth. Not sure if from being pushed out by other kittens, or desire for adventure.

Ongoing problem with rheumy eyes and nose; eye and nose symptoms have always has been right-sided. Vet thought she might have polyps, but she hasn't been examined for them. (Not sure I would want to submit her to surgery if she did have them. Would prefer a more non-intrusive approach.)

Symptoms have diminished with age, though I am concerned that they will worsen again as she becomes a senior.

Eye/nose symptoms seem to have been alleviated somewhat with a food that has less corn, making me suspect a corn allergy. Sometimes nose discharge is light greenish (indicating infection?), but she doesn't seem to exhibit any other cold symptoms (sneezing etc.)

Unlike other cats seems to prefer grain-based foods over meats. Does like the gravy of the canned meats. Unlike other two cats eschews all raw meat (beef, chicken, fish). Only likes canned fish and not canned beef or chicken.

Most social of three pet cats. Likes to be with humans more than the other two cats, but does play with them. (May be the bottom of the cat hierarchy.) Tends to sleep alone or with human (and infrequently with the other cats). Does not like being held on her back at all; she'll struggle like crazy to upright herself; however, loves to be petted. When she sees other cats being petted she'll try to "cut in". Will seek out lap to sit on. She'll also stand on hind legs to get strokes, pushing into hand repeatedly.

Often seems to be the most intelligent of the three. She has played fetch, returning numerous times with the item for person to throw again. Wasn't taught this; she initiated this herself. Likes to push pens off surfaces, but loses interest once they hit the floor. Will fish things (like q-tips and rubber bands) out of the garbage, making it necessary for me to keep garbage away from her. Knows how to get into cat food bags, making it necessary for me to keep them sealed. Will drag food out of bag with paw or will stick head into it to eat. Will also paw food out of hand as you feed her. Drags food out of bowl to floor sometimes. Not finicky about drinking water like one of my cats. Can be standing or moving water, she doesn't care.

Insistent, persistent meow when she wants to be fed. Sometimes will bite ankles to get fed. Used to bite and pull on hair to be fed, but cured her of that. Sometimes she'll stop meowing and seem to forget she is hungry if I don't feed her or if I feed her a tiny amount.

When she is picked up she clings to the surface she is being picked up from, extending her claws and digging in. Seems to be a kind of insecurity.

Appears to sleep less than the other cats during the day, though maybe she sleeps more at night than they do.