Scotland's food standards watchdog has launched a consultation on how to make the food people consume while eating out healthier.

Food Standards Scotland (FSS) said that many "out of home options" are skewed towards less healthy choices and that excess calories, added sugars and lack of fruit and vegetables can all cause people to eat more calories than they realise or intend.

It noted that large portion sizes contribute to the problem, with a recent survey of a sample of chip shops in Glasgow showing the average portion of chips was close to 1000 calories, almost half an average woman's daily calorie requirement of 2000.

FSS has outlined a range of proposals which focus on calorie reduction across the sector with the aim of maintaining choice and the availability of favourite foods.

Proposals include smaller portion sizes, an increase in fruit and vegetables, provision of calorie and nutrition information for consumers and shifting the focus of deals and promotions from unhealthy to healthier options.

The watchdog is urging members of the public and those working in the out-of-home food sector to respond to the consultation which is published on Thursday.

Ross Finnie, chairman of Food Standards Scotland, said: "We recognise the out of home sector makes an important contribution to the Scottish economy, but it doesn't always support a healthy diet.

"There is a real opportunity for the public sector in Scotland to set the standard for healthy eating out of home, by implementing measures now such as clear calorie labelling, cutting down on calories and reducing portion sizes.

"We owe it to the younger generation to provide access to healthier options when eating out and shift the focus away from unhealthy, high calorie foods, without losing the enjoyment that comes with eating out."

FSS said there appears to be public demand for change with more than two thirds (68%) of people in Scotland believing cafes and restaurants should display calories on menus while 82% support greater availability of smaller and half portions of standard-sized menu items.

Public health minister Joe FitzPatrick said: "We are looking forward to engaging with all parties in this to improve the food and drink available outside the home and ensuring the changes made will be reasonable and proportionate.

"Through our Diet and Healthy Weight Delivery Plan, we are taking decisive action to deliver positive outcomes by helping to reduce serious health problems, such as type 2 diabetes, cancer and heart disease, which are commonly caused by eating a poor diet."

The consultation will be open for responses until February 28 2019.