I'd actually look at this a different way: they are happily training you to give them food because they get rewarded for simply fussing about and acting hungry.
Mine look hungry all the time -- it is a cavalier 'thing' along with a handful of other breeds (labs among them) as most seem to lack, probably at genetic level, the ability to ever feel 'I'm full'. In humans this issue, which leads to gross obesity, is increasingly understood as a genetic change (there was a recent Horizon programme in the UK on this).
With humans, who can open cupboards or buy treats, managing obesity is more difficult. With animals, whose food is controlled by us, the answer is more one of -- yes, owner self restraint. I would never give my dogs extra foods to make them feel full throughout the day (though I do give them regular treats especially 'fillers' like carrots
)and I certainly would not give them any type of treat in the morning in advance of a meal and especially not if they are beginning to wake earlier and earlier to actually demand food! That is simply had on you.
So I'd totally ignore that kind of behaviour. They simply do not need to made to feel full all the time by giving lots of low cal/co cal 'filler' treats -- which again only maintains the expectation of having full bellies all the time.
Every single cavalier I have owned is always ready for food, and is a 'problem' eater in that not one could eat what is needed and walk away, or avoid stuffing themselves to a dangerous level of risking bloat, given the opportunity. Lily looks constantly for food scraps on the ground while on walks. She was grossly obese when I got her out of a pound -- nearly twice her healthy weight.She went on a slow reduction/exercise programme, never was on a diet/filler food (though many find these helpful, but I just reduce the amount fed and add back in something like frozen green beans or grated carrot), and never got extra treats to compensate (and keep her wanting the same huge amount of food in her belly all day long...). She's been a heathy weight ever since, runs like the wind, and has learned to not pester for food because she and the others simply don;t get it for pestering as that trains them to pester and rewards such behaviour time after time. They do get a few treats throughout the day, fruit/veg or chews or the occasional dog biscuit, but not every time they look hungry or it would be all day long.
Obesity is the number one health risk for our dogs and has a severe impact on heart health, which will be an issue nearly every one of us will eventually face with a cavalier -- we all have to learn to ignore the normal and exasperating constant cavalier demand for food. For that matter they don't even 'enjoy' most treats anyway -- they inhale many without even chewing or tasting them. So I'd keep a light hand even with fruit/veg treats and certainly don't let the dogs start to shape when people wake up simply because they learn to expect food when THEY want it rather than when WE (sparingly!) give it.
It's great that the trachea surgery has worked so well. :flwr: What a change that will make in her life!
BTW if you have a dog having any kind of seizure on walks -- I would not walk them until they reach that state and need to be carried back; that really sounds alarming and a serious risk. Some dogs for heath reasons really cannot do long walks (often because of poor hearts for example) and sounds like she maybe needs a separate short walk?