Not sure what the book is, but I just read Barbara Kingsolver's
Animal, Vegetable, Miracle, which is the account of her family's attempt to eat locally for a year (though they did buy things like coffee, tea, etc.)
I'd have to do a little more than 100 miles though, or I'd have a VERY limited diet.
We do grow our own veggies, as well as strawberries, raspberries and rhubarb, and my DH fishes so we have lots of salmon. There is an organic farm about 1/2 mile from us, and I get things I don't grow there (and at a farmer's market), but so much stuff is just not available locally for 8-9 months of the year.