Just to be on the safe side, I would claim both Kosher and Halal.

My employer used to have (IMO) extremely generous per diems. If they'd reduced them by a third, I don't think anyone would have suffered - in most cases I couldn't spend the full amount even if I tried.

But instead, when they decided that travel expenses were too high, they replaced per diems with company credit cards (to be used when possible) and (if cc could not be used) reimbursement to employees of actual cost. There was no official daily limit; it was up to each employee to guess what was "reasonable" and then up to the employee's manager to decide whether they agreed that it was "reasonable." Needless to say, some employees were more thrifty than others; some managers were more accommodating than others, and in the end it's not clear it saved any money.

It did, however, increase the amount of time (during working hours) for the traveler to keep receipts and submit expenses, and for someone else to double check it and arrange reimbursements. But I'm sure they think this is a sensible use of time.