Many local authorities have found their furnaces to be too narrow to deal with wider coffins and in some areas coffins have to be transported to other crematoriums that can accommodate them.
Around 430,000 people are cremated in Britain each year. Standard coffins range from 16 to 20 inches but in some areas coffins of up to 40 inches are being ordered to fit bigger bodies.
Government statistics predict that there will be 12 million obese adults and one million obese children in the UK by 2010 unless the nation's health begins to improve.
Lewisham council has ordered a special cremator from America, measuring 44 inches in width and is now taking orders from coffins as far away as Gloucester and the West Midlands.
In Mintlyn Crematorium in Bawsey a new furnace installed by King's Lynn and West Norfolk council accommodates coffins a metre wide.
Councillor Hazel Harding from the LGA said: "As long as the nation keeps on piling on the pounds, pressure will continue to be placed on crematoria. This is just another demonstration of how the UK's obesity problem is putting a real strain on public services.
"The death of a loved one is always a difficult time and having to decamp to another area for the cremation just adds to the ordeal. It is important that grieving relatives get the service they deserve and councils are doing what they can to accommodate larger clients locally."
Tim Morris, chief executive of the Institute of Cemetery and Crematorium Management, added: "The institute has received calls from funeral directors from all parts of the country whose local crematorium is unable to cremate large coffins.
"The likelihood is that a large number of facilities will be upgraded to meet these requirements with some taking this opportunity to install a larger cremator at this time."
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.