Foods labelled as organic are viewed as healthier by many people, with some even believing the calorie content may be altered, a new study has shown.

Organic products are those grown without the use of synthetic pesticides or fertilisers. Animals that produce products such as meat, eggs and dairy products are also not given any antibiotics or growth hormones.

Previous studies have shown that if a food is labelled as organic, many people automatically perceive it to be healthier. This is known as the ‘health halo effect'. However, US researchers set out to determine if this effect goes even further.

They asked 115 people to taste three pairs of products - two cookies, two yoghurts and two portions of crisps. One item of each pair was labelled as organic, while the other was labelled as regular. However all of the products were organic and each pair was identical.

The participants were asked to rate the taste and calorie content of each food item. They were also asked how much they would be willing to pay for such a product.

The results suggested that people's perceptions of food were significantly influenced by the organic label. In the case of the yoghurts and cookies, the participants estimated the ‘organic' products to have significantly fewer calories even though they were the same as their ‘regular' counterparts.

People were also willing to pay up to 23% more for the ‘organic' products.

In some cases, the participants felt that the ‘organic' yoghurts and cookies tasted as if they were ‘lower in fat' than the ‘regular' ones. While many felt the ‘organic' cookies and crisps were more nutritious than the ‘regular' ones.

The organic labels even appeared to affect the participants' tastebuds, with some people stating that the ‘organic' foods had more flavor.

The study found that overall, those less susceptible to this health halo effect appeared to be those who regularly purchase organic foods, those who regularly read nutrition labels and those who exhibit ‘pro-environmental behaviours', such as recycling.

The study was carried out by researchers at Cornell University.