Leonardo, i agree with what day. My Dad did estimates for jobs all day long. He constantly was doing calculius in his head and geometry. He ate a lot of walnuts for brain food. He loved peanuts and other brain foods. You can google what foods are for the brain, the eyes for sight which is brain strain, and etc. I think you will find that these are snackables and help stave off hunger and make one satisfied until you can get home. There are many wonderful sites on line to help with what you are asking about. tc