Sniffing a lemon makes people feel slim, according to new research.
The aroma boosts body image and improves self-esteem, scientists say.
Lead author Giada Brianza, a Ph.D. student, said: "Our brain holds several mental models of one's own body appearance which are necessary for successful interactions with the environment.
"These body perceptions are continuously updated in response to sensory inputs received from outside and inside the body.
"Our study shows how the sense of smell can influence the image we have in our mind of our body and on the feelings and emotions towards it."
The study at the University of Sussex's Computer-Human Interaction (SCHI) Lab found participants felt thinner and lighter when they experienced the scent of a lemon.
On the other hand, the pungent smell of vanilla had the opposite effect - making them feel thicker and heavier.
Brianza said: "It could lead to novel and more effective therapies for people with body perception disorders or the development of interactive clothes and wearable technology.
"They could use scent to enhance people's self-confidence and recalibrate distorted feelings of body weight."
The findings presented at an international conference on human-computer interaction in Paphos, Cyprus, is the first to analyze how smell affects body image.
It is believed nearly 3.5 million people in the UK suffer from an eating disorder, and around 30 million in the US.
Co-author Dr. Ana Tajadura-Jimenez, of the Carlos III University of Madrid, said: "Our previous research has shown how sound can be used to alter body perception.
"For instance, in a series of studies, we showed how changing the pitch of the footstep sounds people produce when walking can make them feel lighter and happier and also change the way they walk.
"However, nobody before has looked at whether smells could have a similar effect on body perception."
Lab head Professor Marianna Obrist said: "Previous research has shown that lemon is associated with thin silhouettes, spiky shapes and high-pitched sounds while vanilla is associated with thick silhouettes, rounded shapes and low-pitched sounds.
"This could help account for the different body image perceptions when exposed to a range of nasal stimuli.
"One of the interesting findings from the research is sound appears to have a stronger effect on unconscious behavior whilst scent has a stronger effect on conscious behavior.
"Further studies need to be carried out in order to better understand the potential around sensory and multisensory stimuli on BIP."