a) Hunger is not an emotional state. It may be an input to one's emotional state but I think that its impact is usually quite weak. b) Overly simplistic example-- do mature adults really have such wide ranging emotions during a conversation over whether there is pizza or not in the fridge?
a) Fair, although I think the author's justification for describing it as such is reasonable. b) Sure, but I don't think maturity is the point. I think the point is to establish a way of thinking about emotions—which I suppose might be more useful the less mature a person you're dealing with.
Hunger itself isn't an emotion. It's a complex of physical sensations. However, in most people, it is highly coupled with various emotional responses. Hunger is one of the first things an infant experiences, often coupled with being fed by a parent and loved upon. It's not accident that a lot of people (not everyone) eat more when they are stressed. (Comfort food). I have seen otherwise mature adults regressed to childhood, infantile behaviors because they skipped a meal.
It's actually a fairly immature understanding of emotions to associate poor emotional control or behaviors with the level of maturity. Your ability to handle emotions has more to do with whether you fully pay attention to the emotions and process them out. Although people with greater physical age will tend to have experienced a wider range of emotions in a variety of life circumstances, if they don't pay attention to them when it happens, it festers in the back of the mind, carried on for years.
I think this model is a "good try". It seems good enough for now, for the author. And although it scratches the surface, I think it's great for anyone to think about this more closely.
To really start digging in there, you have to allow yourself to experience the emotion; "thinking" about an emotion without allowing yourself to experience it or be aware of it tends to be a way for the mind to avoid experiencing painful things.