But new research suggests that even pictures of these kinds of food can make it harder to stick to your diet plans.
Researchers at the University of Southern California, Los Angeles, performed brain scans on 13 obese young women to see how they responded to images of tasty looking treats.
Participants were given two brain scans while they looked at a range of images of foods, some of which were high-calorie - such as ice cream or cupcakes - while others were low-calorie, such as fruits and vegetables.
The women were then asked to rate their levels of hunger on a scale of one to ten, as well as their desire for sweet or savoury foods.
Looking at images of high-calorie foods was found to increase activity in areas of the brain that control appetite and reward to a far greater extent than the low-calorie foods.
However, looking at pictures of non-food items did not lead to the activation of these brain regions.
In addition, viewing high-calorie food images typically led to increased ratings of hunger and desire for both sweet and savoury foods.
The team's findings were presented at the annual meeting of the Endocrine Society in Houston, US, by senior author Dr Kathleen Page.
Dr Page revealed: "This stimulation of the brain's reward areas may contribute to overeating and obesity.
"We thought this was a striking finding, because the current environment is inundated with advertisements showing images of high-calorie foods."
The researchers also found that drinking 50g of sugar halfway through the brain scans led to an increase in ratings of hunger and desire for savoury foods.
"These findings suggest that added sweeteners could be one of the main contributors to the obesity epidemic," Dr Page added.