(1) An inmate is not allowed (essentially, by the society) a specific diet dictated by his/her belief; and, (2) A poor person cannot afford (essentially, because of the society) a nutritious and delicious meal dictated by his/her needs or wants.

What are the differences between them? Are there differences at all?

(1) is a negative liberty: freedom from being forced to eat a certain diet. (2) is a positive liberty: actual ability to eat a certain diet. Western society is still mostly blind to the latter type of liberty.

Similarly, everyone is free to own a home, but ensuring everyone has the means to actually do so is just not something politicians will even talk about, and is often labelled as "communist" or some other kind of thought-terminating label. Everyone is free, some people are just freer than others.