Weighing 11 pounds isn't exactly helpful. Cats can weigh anywhere from like 5-15 lb on average. If she were 20 lb, we could definitely say she's overweight.
If you stand over her and her waist doesn't go inward, just like a person's should, she's overweight.
If you gently feel along her ribs and you have to put more pressure than a soft touch to make out her ribs, she's overweight.
I hope you didn't cut down her portions too much - if she IS overweight and she eats less than necessary daily, she's at risk for Hepatic Lipidosis, or Fatty Liver Disease. You have to go very slowly with cats.
If you want her to lose weight but remain healthy, get her a grain-free canned cat food.
No dry, dry food only promotes dehydration, UTI, obesity, diabetes, and a plethora of other health problems.
Since cats are obligate carnivores (meaning they can't pull nutrients out of plant-matter), all grains and other plant matter does for them is pack on pounds. And since grain-free canned foods are made with mostly real meat and few "veggie fillers" - they don't eat as much of it, but they still get more nutrition than they would from a cheaper brand, so in the end you're paying about the same.
This is also because they're higher in calories (being more nutritious) so 2 of the 5.5oz cans daily of something like Nature's Variety Instinct, Wellness, Wellness Core, or Merricks should do just fine.
I'd also like to suggest you look into raw feeding. Granted, not everyone is thrilled about the thought of giving their animals raw meat (my parents certainly aren't, and my mom still follows Dusty around with a lysol wipe every time he eats, lol) but it's still something healthy, and incredibly inexpensive for a cat, to look into.
Good luck with kitty, I do hope she's not overweight though.
ETA @ add.details: "Tortoiseshell" isn't a breed, it's just a coat pattern. So her being a Tortie doesn't really tell us anything. Technically, she's a Domestic Shorthair or Longhair (assuming short) with a Tortoiseshell coat pattern. Since 97% of the cats in the world are DSH/DLH, there's really no weight/size estimate other than "they can weigh anywhere from 5-15 lbs."
She isn't overweight at all. Depending on the cats size and breeds, cats can weigh anywhere from 4 to 16 pounds.
an adult female cat should weigh 9-10 pounds so she is not that over weight when me and my partner took on his family cat from his parents she was 6 pounds over weight and it took her 6 months to lose it just keep doing what your doing just be careful she doen't lose too much
I don't think she's overweight but you should ask your vet's opinion.
Also, look at what food you're feeding her, you may not need to reduce portions but get a food that is more filling and nutritious so she will eat less and be full faster
My 21 month old male cat is 10 pounds, he's small-ish though, for a male. I had a tortoiseshell female before and she was about the same (10 pounds)
Torties are a color of cat - many breeds and mixes come in a tortoiseshell color.
Average females are 7-10 lbs; males 9-12 lbs. If she is only a year and she's 11 lbs she is on her way to become very overweight by the time she is 2 yrs old and done growing. Unless this cat is a large breed like a Maine Coon she is too heavy at her age.
First do NOT free feed - give her no more then 1/4 cup of dry and 1/3 (6 oz can) of canned food - one meal dry, one meal canned. All dry tends to create fat cats.
The average weight of a female cat is 6-8 pounds. Outdoor wild cats tend to eat once a day to every other day. So it would not be inhumane to only feed your cat once a day rather than twice. Using a diet dry food will help also. Not giving treats or table scraps. And continuing play everyday. If you only have the one cat, possibly getting a second cat for her to play with. It will take some time to notice weight loss...to a cat, 1 pound is A LOT. So do not be discouraged if it doesn't seem like she's losing. Give it some time. If after a month or two you don't notice a change...then you may want to consult a vet about prescribed food. She really only needs to lose about 3 pounds to be healthy.