Homemade isn't equal to healthy.
Some homemade dishes can very fattening. I make a mean lasagna which is a heart attack on a plat, oozing with cheese. I cook everything from scratch, even my own bread, some dishes are healthy, others not at all.
Maybe increase the quantity and variety of vegetables, making it a challenge to eat 20 different ones every week. So green beans salad with tomatoes, red onion, and tuna for one meal, grated carrot with parsley in the evening, a pumpkin and carrot soup, asparagus grilled in a pan, celery salad with orange juice, roasted leeks, and so on, with always a main like a steak, grilled chicken breast, an omelette,
So instead of removing, you add stuff. Increase the variety of vegetables will also change her gut bacteria for more healthy species, defiantly increase her fibre intake, and also help with moods.
Make it something to look forwards. Pick a new veggie each and look for recipes. Kale chips, fennel salad, learn to do dressing, vinaigrette, and then test the taste in the evening or weekend,
The human body is very resistant to changes, and will try to save weight instead of losing it. So trying to make changes that have little to no impact on weight will lead to frustration.
If you only reduce quantity instead of changing the what, she will just suffer.