For many of us, mornings start with a bowl of cereal, be it cornflakes or branflakes or granola or porridge. So why are cereals such a popular breakfast food? Agnes Bouchier Hayes from Technological University of the Shannon joined the Today With Claire Byrne show on RTÉ Radio 1 to discuss the history and the health implications of that bowl of rice krispies. (This piece includes excerpts from the conversation which have been lightly edited for length and clarity - full discussion can be heard above).

It begins with the ancient Romans. "Porridge goes back as far as ancient Rome", says Bouchier Hayes, "and . they were a society that actually had food on the go to begin with. Breakfast cereals as we knew them today really began in the 1800s in America. If you think about Little House on the Prairie and what they would have had, they would have had whole wheat flour made into a hard biscuit or dough, and that would have been allowed to sit in milk overnight, the original overnight oats I suppose.

"After World War II, there was a big surge in breakfast cereals because of clever marketing campaigns, but also the introduction of sugar and the progression with what could happen with consumer foods and ready foods."

'There's a nutritional declaration on every food product that you buy inside in the supermarket and this is a really useful tool.' Photo: Getty Images

That's where the sugar comes in. "Sugar has become an integral part of all these breakfast cereals. We like sugar as human beings. We really like sugar and the sugars that are being used are really sweet and they have a function to make sure that the cereal can be crunchy, to make sure that it holds its texture in the milk and also to give it shelf life."

Sales of cereals are on the rise, but not the ones aimed at kids. "Sales of the sugary cereals have come down in Ireland over the past 12 months for children's. However sales of cereals themselves have increased. The adult ones have increased and that was because they were putting some of this down to stockpiling. They're a reasonable cost, you can feed people regularly throughout the day with the more adult type ones and you can store them easily."

One thing which people should remember when it comes to sugar is portion size. "When I looked at the cereals and the different types of cereals, it's all 'per 100 grams' on a label on the back of a pack," explains Bouchier Hayes. "Now, if you weighed out 100 grams of Coco Pops, you'd nearly need two bowls. It's a lot of Cocoa Pops or cereal or Rice Krispies. The average that I looked at then was 40 grams, which is what an adult would consume. As children are smaller, give them smaller amounts.

A bowl of porrige was good enough for the Romans

"With Coco Pops and Frosties and sugar coated cereals, there's very high sugar, they're very sweet, and the sugars flavor is created for that sweetness. It's either sucrose, fructose and it's an invert sugar so it's very, very sweet. If we can tone down the sweetness a little bit, that might help, like adding Rice Krispies to Coco Pops, a little bit of Corn Flakes to Frosties. They're still having some of goodness but not necessarily the amount of sugar that can be present."

What about sugar and adult cereals like granola? "Some of the cereals, like a cluster cereal, are made by combining ingredients like nuts, rolled oats, puffed rice, things like that, and these rely on glucose syrup. It has a sweet flavor, but it also acts as a setting agent when it's warmed. If you're eating a cluster, you're eating it for that, to have that little bunch, that little cluster together so that sets as a solid.

"People who are making granolas themselves at home will see the amount of oil and the amount of sugar or honey that is put into that. Don't think that you're having a more wholesome cereal because you're having a grain and you might have dried fruit and all those lovely, wonderful ingredients. You're also adding sugars and oils to those ingredients so just to be aware of that."

Look at the sugar and think 'do I need that extra amount of sugar?'

From a health point of view, what should we be looking for on labels when it comes to the right cereal to take from the shelf? "There's a nutritional declaration on every food product that you buy inside in the supermarket and this is a really useful tool that you can measure what you're looking at against any other product in the shop.

"You'd look at the sugar. You can look at the calories, but most cereals are pretty low in calories. But look at the sugar and think 'do I need that extra amount of sugar?' If you look at a packet of chocolate coated, puffed rice and you look at that product, you'll see that the fibre would be quite low and there's nothing to give you fibre. Whereas if you look at a cluster or a granola or a muesli type thing, you will see that on the front of it, there is dried fruit in it."