Tonga rated as the world’s seventh most obese nation, and the country’s life expectancy has fallen over the decades.
Mr Pohiva said he would urge his fellow Pacific leaders to join his competition when they meet at next week’s Pacific Island Forum.
“I will make a proposal to [them] next week: we should all get together for a weight loss competition; for an entire year, so when we meet the following year we will weigh in again and see who has lost the most,” Mr Pohiva told the Samoa Observer.
“Once the leaders are adapting to that mindset they would be determined to get their people on the same aspect and go from there.”
Mr Pohiva said his competition could breathe new life into the fight against obesity.
“Pacific island leaders meet and talk and talk about this issue, yet initiatives are not making an impact,” he said.
“We have been advocating the same issue over the years, but it doesn’t seem to work.”
There were a number of theories as to why the Pacific Islands saw such high rates of obesity.
Much of the local diet consists of imported and processed foods.
Some observers saw obesity and a sedentary lifestyle as an indicator of wealth.