Plans to restrict the term "Cornish pasty" to products made only in Cornwall have led to protests from food manufacturers outside the county.
The pasty is worth about £150m a year to the county's economy
The government says it has received objections from companies which fear their businesses may suffer.
A European Union initiative called Protected Geographical Indication Status stops locally produced foods being imitated by non-local brands.
St Ives MP Andrew George said the "traditional" dish needed safeguarding.
Food for thought
Mr George said the Cornish name should not be "stolen" and urged people to write to Food Minister Lord Whitty backing him.
He said the need to "establish a distinctive Cornish brand image is very important to the Cornish economy".
The county's other MPs have also put their support behind getting protected status for the pasty.
Lord Whitty said objectors had claimed "Cornish" was a "general term for pasties" and that companies manufacturing them outside the county could see their businesses suffer.
He said objections must be considered before any ruling.
Other well known products which have benefited from protected regional status are Newcastle Brown Ale and Melton Mowbray pork pies.
Recent research found Cornwall's most famous fast food is worth more than £150m a year to the county's economy.
The Oxford English Dictionary suggests that the pasty was identified in around 1300.
It became more commonplace in the 16th and 17th Centuries, and by the 18th century was firmly established as the staple diet of working men across Cornwall.