Heightened Sense of Smell Linked to Obesity

The following article will be featured on an upcoming episode of Dr. Asa on Call with Dr. Asa Andrew:

We all know our noses can often lead us into temptation when it comes to food.

Would you really eat all that popcorn at the movie theater if that buttery smell was not wafting out into the street? But for people who are obese, sense of smell may play a bigger role than we realize in causing them to eat too much.

A new study from researchers at the University of Portsmouth in Great Britain has demonstrated that people with a higher body mass index also have a much more heightened sense of smell compared to thin people, particularly following a full meal. The research, published in the journal Chemical Senses last month, may help explain why overweight people eat more.

Leady study author Dr. Lorenzo Stafford says that that keener sense of smell may lead an overweight person to keep eating even though he or she is already full. The study included 64 volunteers asked to take tests in smelling ability both before and after eating a complete meal.

Dr. Lisa M. Davis, vice president of research and development with Medifast Inc., a physician-developed weight-loss system, reviewed the British study and told AOL Health that while it might seem counterintuitive, that heightened sense of smell following food consumption may actually help most people know that they are full so they stop eating.

"But for those with a higher BMI, greater olfactory sensitivity to the smell of food may actually foster the continuation of eating, as opposed to causing them to stop eating like individuals with a healthy BMI," Davis adds. "Obese consumers with a higher BMI have more of a drive to eat high fat, high sugar and highly palatable foods, which is consistent with a heightened taste sensitivity for these foods."

Davis goes on to explain that the opioid receptors in the brain drive the palatability of food, while dopaminergic receptors drive motivation for obtaining good tasting food to eat. "Studies have shown that obese individuals tend to have a dysfunction among these regulatory systems," she says.

But all of this begs the question as to whether obesity is driving the heightened sense of smell or whether the heightened sense of smell is driving one to eat more, leading to obesity. Davis says it's not a question she can answer, "but it makes a fascinating area of future research."

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