The report claimed obesity is increasing in rural areas
Health chiefs on Shetland have dismissed research which claimed the islands were the fattest area of the UK as "misleading and simplistic".
The so-called "fat map" released by a pharmaceutical company said almost 16% of Shetlanders were obese.
But NHS Shetland said the results were based on flawed research.
Elizabeth Robinson, health improvement manager, said she was "confident" that obesity rates in Shetland were actually well below the national average.
The map, created by Dr Foster Research and sponsored by Roche, which manufactures an anti-obesity drug, suggested the problem of obesity was increasing in rural areas.
It said Shetland had the highest obesity rate in the UK, at 15.5%, with Orkney and the Western Isles also featuring highly in the list of the supposedly fattest areas of the country.
New Scottish Liberal Democrat leader and Shetland MSP, Tavish Scott, said he was "highly scpetical" about the survey.
"It's clearly important to track obesity and to offer help to those who are overweight, but it is absolutely ridiculous to suggest that Shetland is an obesity hotspot," added Mr Scott.
Parts of the west of Scotland, including Glasgow, which are traditionally seen as obesity hot spots, fared far better in the Dr Foster Research league table.
But Ms Robinson said the Shetland statistics had been based on 1,000 patients at a single GP practice.
She said the doctors at the practice saw every one of the patients on a regular basis, so could say with certainty that 155 - or 15.5% - of them were obese, a figure that is actually about 7% less than the official UK obesity rate.
'Too far to walk'
And she pointed out that obese patients in large urban areas were far less likely to visit their GP, resulting in artificially low statistics being returned from doctors in those regions.
She added: "It is slightly misleading and too simplistic to say that Shetland has the highest level of obesity in the country - in fact I can say with confidence we are actually well below the national average for obesity.
"However, we hope to publish a healthy weight strategy shortly, which will include measures like improving public transport, because people on Shetland are more likely to take the car because the distances are too far to walk and the inclement weather."
Ms Robinson also described Shetland's leisure centres as "fantastic", but said the NHS was looking to increase the number of people who used them.