Subsistence payments in the private sector

How common is it for subsistence payments to be made in the private sector? I'm in my current role less than a year and raised the issue of subsistence payments where I'm working away from the office at various sites for more than 5 hours. The company provides a company van and parking fees are reimbursed but no subsistence is paid. I was paid subsistence in my last job but I'm told its not company policy here. I think it's a bit mean, especially if there's a lot of travel involved and a long day of work to be done. I don't do a lot of work away from office, but the cost of basic subsistence could add up over time. Am I being unreasonable?