The study by Robert Gordon, Abertay and Newcastle universities found no increase in the consumption of fruit and vegetables and of oily fish over the period.
The “energy density” of diets has increased, and while there was a small reduction in the levels of free sugars and saturated fat, they still remain too high in relation to national dietary goals. Red and processed meat consumption did reduce over the period, with the average meeting the target.
Households in the most deprived areas of the country were found to eat significantly less fruit and vegetables, oil-rich fish and fibre than those in the wealthiest areas.
Nutritionist Dr Karen Barton, from Abertay University, said: “We found differences in dietary intake by deprivation – with households in the most deprived areas consuming significantly less fruit and vegetables, oil-rich fish and fibre than those in the least deprived areas.
“However, intakes for all groups of the population were considerably lower than the Scottish Dietary Goals. The fruit and vegetable recommendation in particular is well-known – five portions per day – however that awareness does not seem to translate into changes in our dietary behaviour.”
Principal investigator and nutritionist Dr Lindsey Masson added: “In Scotland, 65 per cent of adults are overweight and 29 per cent of adults are obese. Therefore, it is essential that we start to reduce our consumption of foods that are high in sugar and fat – namely biscuits, confectionery, crisps, cakes, pastries, puddings and sugar-sweetened drinks.
“In addition to raising awareness of the health benefits of meeting dietary recommendations, the Scottish Government needs to support the population in achieving these dietary goals.”
Researchers used food purchase data from the UK living costs and food survey to look at annual trends in food consumption and nutrient intakes between 2013 and 2015, comparing these to figures from 2001 to 2012.
The study, funded by Food Standards Scotland, was designed to monitor progress towards the Scottish Dietary Goals, last updated in 2016.
Liberal Democrat health spokesman Alex Cole-Hamilton said the report was a wake-up call for ministers.
He said: “The national obesity epidemic already puts a huge strain on our NHS. Unless we take action now we are sitting on obesity time bomb that will only increase pressure on services. Healthy eating and lifestyle choices start in childhood so it is essential that parents get the support they need to give their children a healthy start in life. That means ensuring they are educated about how to stay healthy and have the opportunity to exercise and take part in physical activity.”
The Scottish Government has set out plans for a crackdown on supermarket multi-buy deals for foods high in salt, fat and sugar to encourage healthy eating, as part of a national Diet and Healthy Weight Delivery Plan.
“Too many people in Scotland face serious health risks linked to poor diet and unhealthy weight,” a Scottish Government spokesman said.