I have to declare something here: my job prior to being on maternity leave was obesity research in one of the world's top universities, so I do feel I have done the research!
The spray is homeopathic. That means, as far as I understand homeopathy, that there won't actually be any molecules of HCG left in the bottle, but that the water after the serial dilutions will "retain the memory" of the HCG. Hmm.
As for HCG itself, it is produced by the embryo and later the placenta, to provide the uterine lining for the embryo to implant and may have a role in immunosuppression, so the body doesn't recognise the growing baby as 'foreign' as it would, for example, a virus. HCG isn't nutrition for the baby. The baby feeds on nutrients from the mother via the placenta.
I wonder if you could, in the absence of any papers, explain what the right sort of fat and the wrong sort of fat is?
We have subcutaneous fat, which is what makes us look fat if there is lots of it, and visceral fat, which is on our organs and muscles and predisposes us to insulin resistance and then all the problems associated with that. We can have lots of visceral fat without looking fat, so people of normal weight overall can still be insulin resistant/have diabetes.
VLCDs do work because you don't take enough energy in, so your body starts breaking down your subcutaneous and visceral fat stores. This in turn does mean that you lose plenty of weight, which will certainly lead to improvements in insulin resistance and diabetes, cholesterol levels, blood pressure and, more than likely for a number of physiological and psychological reasons, make you feel fantastic.
This is just a VLCD hiding behind pseudoscience to make it something it is not.