Have you been feeling sentimental in the supermarket snack aisle recently? Is that feeling pushing you to reach wistfully for a certain chocolate bar or biscuit more than usual?

If so, you might not be alone. That's because your favourite snack foods have been injected with a healthy dose of nostalgia.

Consider these recently released products – Vegemite shapes, Arnott's chocolate blocks studded with Jatz, Scotch Fingers, Wagon Wheels and Ginger Nut biscuits, Cadbury's popcorn chocolate blocks, Smith's chips flavoured with spaghetti bolognaise, snag 'n' sauce, Peking Duck and mac 'n' cheese, strawberries and cream M&Ms and even milk flavoured with Mint Slice and Iced Vovo.

It's the latest way clever food manufacturers are trying to sell us their snacks and it sounds like it's working.

"The response has been overwhelmingly positive," Arnott's Asia-Pacific chief marketing officer David McNeil says. "The number of conversations that are happening on social media about Arnotts, about these brands and about the innovation is unprecedented for us.

"We have deliberately wanted to spark conversation with things like the Tim Tam Slam and the chocolate blocks and we have been really overwhelmed at the reaction … around the excitement of mixing these classic biscuits in the chocolate block."

University of Melbourne product development expert Professor Angela Paladino said nostalgia-based food items are attractive to manufacturers because they maximise companies' existing intellectual property and brand value. This is keeps product development costs low.

"They need to make sure it can't be seen as the exact same taste as the old product or else there's no point developing a new product line," Professor Paladino said. "You need some form of that identity of that old product in the new one and you need to be able to taste it so people can trigger that emotional memory but it can't be too similar."

McNeil says Arnott's research showed that consumers responded positively to nostalgia motifs, and that incorporating those well known biscuits into chocolate blocks was the perfect way for that to be delivered.

"We know for sure is that consumers more and more are longing for more moments of real connection and with nearly 154 years of heritage, Arnotts has always been one of those brands that acts as a catalyst to bring people together," he says.

"These classic brands do take people back and do take them back to perhaps memories or times when they had more moments of real connection and relationships.

"For us the chocolate blocks are really an innovation that blends the familiar with all of that heritage. But with a contemporary spin to it."

He said people were looking to balance the feeling of being overwhelmed by advancements in technology and access to information with quiet, more simple times.

"Brands that stand for that or reflect that attitude and that shift are on trend," he says.

University of Melbourne consumer psychology expert Dr Brent Coker said nostalgia is a "powerful and easy" emotions for brands to tap into.

He also said these products were popular because they create unfamiliar combinations using the familiar.

"Curiosity comes into it then," Dr Coker says. "If you don't tell them that it is spaghetti bolognaise flavour, chances are they wouldn't have any idea what it is. But you are told, and it plays on curiosity.

"People have that memory already. It's always easier to work on something that's already in peoples' minds, rather than building something from scratch.

"It attracts their attention rather than coming up with a brand new flavour."

Other examples include mixing the classic Gaytime ice-cream with an ice-cream sandwich to make the Gaytime 'Sanga' Ice Cream, Coconut Rough Cadbury blocks and Curly Wurly 'Squirlies'.

Arnott's have even taken the idea of nostalgia to selling an action with their Tim Tam Slam biscuits. They're made specifically to suck milk through.

"It's like an itch, but a cognitive itch. A feeling. And then people want to scratch that itch by acting on it, like curiosity," Dr Coker says.

The trend extends to fast food and restaurants, too. McDonald's is again selling McFlurry's filled with its apple pie while cult Melbourne and Sydney burger chain 8bit has offered Wagon Wheel, Cherry Ripe, Lamington and Bounty milkshakes.

In Melbourne, the recently opened CBD '70s themed Juke's Karaoke Bar serves cabanossi, cheese and chocolate fondue and Chiko Rolls from its kitchen.