KNOWLEDGE is power. That seems to be the message from consumers quizzed by Food Standards Scotland on what changes to the out-of-home food sector should be prioritised in the quest to curb obesity.

There was little support for an outright ban on supersize portions, meal deals or upsizing, but there was an appetite for information.

Participants were shocked by the calorie content in a number of popular meals and said that, had they known, they would think twice about ordering it.

A number of the items featured in the consultation were not necessarily what most people might consider "unhealthy".

A Pizza Express chicken salad came in at 954 calories thanks to a creamy dressing and breadsticks, while a low-fat strawberry yoghurt granola pot from Coffee Republic packed 411 calories, mostly as a result of sugar.

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There was also a 947 calorie meat lasagne from Zizzi, a vegan Katsu curry from Wagamama with 1094 calories, and a KFC meal deal of popcorn chicken, fries, coleslaw and a regular-sized soft drink at 1260 calories.

Asked to guess the calories, the average estimate among the respondents was 500 calories for the vegan curry, 550 for the chicken salad and 200 for the granola pot.

Underestimates on this scale are particularly common for foods perceived to be healthy - the so-called 'health halo' effect.

A separate exercise guided participants through a grid showing that, depending on the portion size and type purchased, cinema popcorn could have as many as 1180 calories, a takeaway coffee up to 420 calories and a large fish and chips some 1900 calories.

"It was clear, very quickly after these exercises were undertaken, that many respondents were left quite uncomfortable," said the report. "The realisation of how little they knew about the implications of eating out-of-home horrified and surprised many respondents."

The research highlights how attitudes to eating out for everything from breakfast, to buying a sandwich for lunch or going out for dinner, had shifted in Scotland from being a "luxury or a real treat" to an everyday occurrence.

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"Historically, eating out of home was regarded as a treat that gave people positive experiences," said the report. "Now, however, the treat that eating out-of-home offers is more often about taking away daily stress and pressure - or just indulging.

"It can be observed that this shift in attitude fits in with the way that people in contemporary Scotland like to (or like to think that we) live our lives now. That is - busier, faster, and more furiously based on instant gratification."

This "instant gratification" includes abandoning the practice of bringing your own packed lunch to work in favour of buying sandwiches or other pre-prepared food, and the sense that "grabbing a coffee on the go was felt to now be a norm".

The proliferation of takeaways, cafes, sandwich shops and restaurants is welcome, but the sheer availability of affordable and tempting food has undoubtedly contributed to the nation's expanding waistlines.

Making calorie labelling mandatory on restaurant menus and food counter displays has the potential to change habits, without taking away consumers' choice or their right to the occasional blow-out.

There should also be support for small and medium businesses, such as delis, who would find it harder to adapt.

Lorraine Tulloch, programme lead at Obesity Action Scotland said: “Last year our work indicated that an average bag of chips could unknowingly provide a woman with half her recommended daily calorie intake.

"The proposed measures will ensure that consumers are fully informed about what they are buying and that the food industry improve their offering.”

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Ross Finnie, chair of FSS added: "Many popular out of home choices, such as burger meals and fish and chips can also contain nearly all of our recommended daily calories in one meal alone."

The proposals dovetail with the push to stop retailers selling junk food on promotion or at discount prices.

Overall, there is a sense that the obesity crisis can no longer be left to personal choice.

As the FSS report states: "Many accept that we, at individual levels, are inherently emotionally weak and lack willpower around food out-of-home. It was felt that this weakness can potentially be overcome by hard facts about calories."