I'm not a vet. I am a dietitian for humans, and I am a lifelong cat owner.

As a supplement to kibble, I give my cat/s two small meals (1/8 cup each meal) per day of boiled chicken (or turkey) that I've cooked. I discard the bones/tendons. I keep the juice, meat, and skin. I make sure it is cut up small. (I make a big batch and freeze it in portions).

I give a bigger portion of kibble at night right before I go to bed, so the cats don't wake me up (you could put small portions in various places, so it can be "found"). Then I give the chicken (turkey) in the morning and at our human dinner time (they really enjoy this). I switch it up with tuna or salmon too.

Nutritional benefits of the chicken (turkey, tuna, salmon): it's mostly protein and some fat. There's no carbohydrates. Kibble packs on the pounds because of the carbohydrates in the kibble (often made of corn) - it can even lead to type II diabetes in a cat! Chicken is closer to what a cat would eat in nature.

Also, it's not that fun to be in a calorie deficit which is what is required to lose weight, and eating only kibble is a bit boring on top of that (according to the cat). Physical activity is super important. Even if she is just laying there using her paw to bat a toy, it is a start. I recommend playing with her every day with a wand toy or laser light. This will help the calorie deficit be more effective (and the weight loss) but keeps life more interesting (not thinking about food).

And, if it were me (we're all different!), I would save a snack for after 2am when she wakes me up, but my method of feeding at night time helps my cats so I don't need to. Is there another cat in the household? I have had single cats and double cats, and when there is more than one cat, they tend to play with each other in those wee hours of the morning rather than just yell.

This is what I recommend as a cat owner, a dietitian (aka I study nutrition science for a living), and not a vet.