Ever wondered why you delight in TV commercials showing junk foods compared to those featuring healthy meals and diets? A new study found that the former triggers positive emotions compared to the latter.

The University of Michigan researchers recently published their study on how the two types of food ads affect the feelings of viewers, particularly their food-related emotional expectations.

They found that commercial shots of juicy burgers, chicken nuggets and creamy milkshakes increased the beliefs of viewers that they would feel positive emotions when they eat those types of foods.

On the other hand, there was no evidence that the commercials for salads and other healthy meals changed the viewers' beliefs of feeling positive emotions when eating those foods.

"Many people think that eating highly processed foods like cheeseburgers and French fries will make them happier, and these beliefs are especially strong in people struggling to control their intake of highly processed foods," lead author and former U-M fellow Jenna Cummings said in a press release.

Through a randomized experiment, Cummings and colleagues observed the effects of food advertisements on food-related emotional expectations in adults. The study involved 718 participants randomly assigned to watch 15-second ads featuring highly processed foods, minimally processed foods, both food groups and cellphones (control).

After viewing the clips, the participants had to complete questionnaires about their beliefs, feelings and behaviors. Many participants who watched the ads for highly processed foods had higher expectations that they would feel positive emotions if they ate those.

"Regulating fast-food advertisements and changing beliefs about how highly processed foods affect emotions could help people eat more nutritious foods," Cummings suggested.

It is important to note that some participants had few symptoms of food addiction or a strong craving for highly processed foods despite the negative consequences. The same group showed increased expectations of having a rewarding feeling when consuming junk food after seeing the ads.

The study published in the Journal of Health Psychology was the first to test the effects of food advertisements on food-related emotional expectations, according to the authors.

A 2015 study showed that eating highly processed foods may seem more rewarding than consuming healthy meals because of the presence of fat and refined carbs in junk foods.

Experts believe the Nutri-score labeling system could help consumers make healthier choices when buying food, thus reducing the risk of several cancers. Peter Bond/Unsplash