The Martian by Andy Weir
Not about an alien Martian, but a man living on Mars.
A diary-style book, but this is not Bridget Jones. There is some calorie-counting though, as our protagonist calculates how much food he has left and how long it will feed him for.
This is the least fictional science-fiction I think I have ever read, in a very near future (I don’t think the date is given) where manned missions to Mars happen, and go wrong. I haven’t looked up the details of the technology but it all sounds and feels very mundane.
Mundane is a good word for this book. Despite the life-or-death situation, nearly every task is in itself fairly mundane, and is described in a very matter-of-fact way. I got to like Mark’s tone of voice and approach to things.