Hiya,
When I was around BMI 25 I started getting VERY hungry. (Hungry and lethargic all day while on SS)
So while it doesn't have to be a sign, it can be a sign in some cases ;-). For me it was a sign from my body telling me; eat more! Hahah.
I did have hunger pangs through the diet a bit, not as bad as the around bmi 25 ones but yea.. I think it's normal but that's all been explained above ;-) Just remember that if you stay strong you'll be fine!!!!
xx