Ever wondered why one crisp is never enough?

What makes Tayto, King, Keogh's and Kettle crisps so tasty and moreish - and are they good for you?

There's nothing like crisps (or even a crisp sandwich) if you're in the mood for comfort food at any time of the year. But what makes those crisps so tasty and moreish - and are they good for you? Agnes Bouchier Hayes from Limerick Institute of Technology has carried out extensive research into all the different brands and types of crisps and she spoke about her findings on the Today With Claire Byrne show on RTÉ Radio 1. Here are some excerpts from the conversation that have been edited for length and clarity.

There are three parts which make crisps as moreish as they are. "There's the salt burst flavour that first hits you in your mouth", explains Bouchier-Hayes. "The next thing would be the fat, that would be coating, the oil that the potato would have been cooked in. And then there's a lot of starch, which is a complex carbohydrate, which has a lot of sugar in it.

"They are very much built to make you reach for the next crisp. It's actually inherently built into us. There's a nerve at the back of our nose that actually sends a message to our brain to say 'yeah, this is really, really good, this is lovely.' It's the same thing you'd have with a toasted cheese sandwich. Biologically we're built to eat more crisps really. It's never just one."

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From RTÉ Archives, Brenda Kneafsey reports for children's show Motley in 1970 about the process to turn a humble spud intp a bag of Tayto Cheese and Onion crisps

So, what about that salt? "We do need salt in our diet", explains Bouchier-Hayes, "and the amount of salt that we would need as adults is about four grams, but we generally take about six grams. It changes throughout life. For a one to three year old, it will be two grams of salt. It changes as we grow so for a four to six year olds, you need three grams of salt. For a seven to 10 year old, then maybe about five grams of salt per day.

"What happens with salt in our body is that it puts a strain on our body. It affects our blood pressure and blood pressure basically shows the amount of work that your heart has to do to pump the blood around your body. When the pressure inside your blood vessels stays at a very high level over a long period of time, that can damage your heart and leads to the problems of heart attack and stroke."

When it comes to crisps and salt, Bouchier-Hayes had crunched the crisps (Keogh's, Tayto, Kettle and King) to come up with the numbers. "When you're comparing them, the labeling in Ireland now has made it much easier because it's per 100 grams. If you look at the back of a label and you're looking at what's called the nutritional declaration, every single one on every single packet of food is laid out the same way. And it's all per 100 grams.

From RTÉ Radio 1's The Business, interview with Tom Keogh, founder and managing director of Keogh’s Crisps

"All of them tended to have up around one gram of salt per 100 grams of crisps. It did vary, with King crisps having 1.4 grams and then Kettle crisps slightly less at 0.9 grams per 100 grams. These were salted crisps. King crisps, to be fair to them, were cheese and onion crisps. And the Taytos, by comparison, were 1.5 grams of salt per 100 grams.

"I don't want to scare anybody on salt because we need it in our diets and it's there for a reason, but we do take in an awful lot of hidden salt in processed foods. For example, if we picked up a pre-made sandwich with bacon in it, a BLT, if you look at the salt in that, there's probably a good deal of your daily intake of salt present there because there is salt in the nitrate that will be in the bacon as well as in the bread. They probably had some in the mayonnaise. We just have to be aware of what we're taking into our diet. And adding a packet of crisps on top of that then, which an awful lot of people would do at lunchtime, just to be aware."

You can hear the discussion in full below

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