Awww, Baby is a great name for a little girl! I have a dog named Baby and several of my birds know that this word is applied to them, too. My male Senegal, Sweetpea, which is a genius at cognitive speech, actually teases/jokes with me saying that his name is Baby Bird when he knows very well his name is Sweetpea.
And I name my male redbelly Davy because it sounds like Baby as I did not know his real name and he kept on saying: "Hey, Baby!"
John [Navre] is correct. Birds cannot consume human cereal - or anything that has been formulated for human nutrition, actually. I know that avian vets and most people say that parrots can eat human food but anybody who says that has not done any real research on their natural diets or their nutritional needs [avian vets don't study parrot nutrition or behavior]. One very serious issue is iron content. Humans need a lot of iron in their diets while birds don't. Cereals are particularly bad because they are mostly formulated for children who need even more of it than adults. For example, the iron content in Cheerios [something that, unfortunately, has been recommended as a treat for parrots for years now] is up to 45 percent while a bird cannot consume more than 2. To make matters worse, birds cannot get rid of the excess iron so it goes into the liver for storage and once the liver becomes saturated, you end up with a condition called hemochromatosis which is fatal and has no cure. I adopted a 10 year old sun conure with this condition caused by feeding her Cheerios. It took me a looooong time of a special iron free diet and special supplements both in the form of liver cleansers and a special iron-free multivitamin/mineral supplement [which the manufacturer of the bird seed mixes I use with my birds kindly had his own vitamin/mineral supplement manufacturer, La Roche, make specially for me] to get her bile acids levels to a good normal range. But she will still require the special diet and supplements for the rest of her life because once the liver is damaged, this is the only way to keep them alive.
So, if you have been feeding her human cereal and other fortified human foods and/or meat, her weight loss could be caused by advanced liver malfunction so, again, you need to take her to an avian vet for a complete physical.
As to leaving the Tropimix in her bowl all day long... well, that's what we call 'free-feeding' meaning, she can eat as much as she wants of it and, when it comes to protein food [seeds, nuts, pellets, nutriberries, avicakes, etc] that's not good for any parrot and I'll tell you why. Nature gives animals a craving for elements that are necessary for life but hard to find. And, like humans with salt, parrots have it with protein because, in nature, there are no rich, abundant sources of high protein for herbivores so, whenever they find one [say, a tree with nuts], they eat and eat and eat of it until it's all gone. We bred these birds in captivity but their physical needs are exactly the same as the ones in the wild so, when we free-feed them protein food, they will eat and eat and eat same as the ones in the wild. I do free-feed but it's gloop and raw produce which they get for breakfast and stays in their cages all day long until it's time for their dinner when they get their protein food in a measured portion. I will tell you what I feed mine as a starting point and you can take it from there. My birds get gloop [this is a very low protein, virtually no fat, very high moisture and fiber dish made out of a variety of whole grains cooked al dente mixed with thoroughly cooked pulses and chopped veggies - if you go to the diet section, you will find several recipes of gloop from super easy to the more complicated one I use myself] accompanied by raw produce [one veggie, one fruit, one leafy green or broccoli]. I alternate spicy and fruity [which I should actually call 'non-spicy' because it's not as if it's actually 'fruity' all the time] gloop by adding spices and chopped produce or naturally dried fruits like raisins, currants, dates, figs, etc [this is because if you add fresh fruit to it, it gets all mushy and wet and at least my birds don't like it]. I give them one single fruit, one single veggie and one single leafy green but they get a different one every day of the week or every ten days - this is because I have discovered that, if I give them a variety, they will pick and choose always the same thing day after day so by giving them just the one, they end up eating a larger range of produce. I also make birdy bread [in the bread machine, not by hand
] and birdy cookies and I always feed organic of the ten 'dirtiest' as well as all the greens [I don't ever feed spinach because it's too high in iron, or collard greens, mustard greens and parsley because they are too high in oxalates].