I should point out that I try to keep my meals within the normal limit, and almost entirely am successful do so. When my meal cost exceeds the limit, I only expense the per diem and consider overrun to be a personal expense rather than trying to justify the overrun.
And I usually don't eat breakfast, and sometimes skip lunch, so since we're reimbursed based on ACTUAL expenses rather just given a specific amount per meal whether we use it or not, that ends up being savings to the company.