Do Diet Foods Satisfy?

February 21, 2011

Are diet foods actually satisfying our cravings for sweet treats? A new study may have just found the answer to this tricky question.

The amount of food we eat is driven by a combination of sensory signals, including those from our stomach measuring fullness, signals indicating a need for nutrients, and sensory specific (i.e. salty or sweet) satiety. Sensory-specific satiety, or the way we feel once we have satisfied a certain taste, is associated with the activation of brain areas in response to both odor and taste stimuli, as well as decreased ad libitum intake.

A new study, published in the journal NeuroImage, adds to the idea of sensory-specific satiety and has found that the brain responds differently to caloric and non-caloric sweet foods. The study investigated brain activity in response to caloric and non-caloric (i.e. regular and diet) orangeade, and found that the caloric beverages affected the activation of the amygdala, the reward area of the brain.

Researchers, from the University Medical Center Utrecht in the Netherlands, pose a possible explanation, “the sucrose-containing orangeade is rewarding due to its caloric content while the non-caloric drink is sweet but not metabolically rewarding (so therefore), less biologically relevant.”

The amygdala is involved in emotional processing of stimuli, and is thought to influence behavior, by dealing with sensory cues associated with reward and by linking the cues to emotion. Previous work has shown that the anticipation of food due to its aroma activates the amygdala, while the amygdala deactivates in response to pleasant tastes.

Researchers choose caloric and non-caloric orangeade in order to reduce and dissociate the effects of satiety based on taste from metabolic satiety.

Researchers reported that the amygdala deactivated in response to caloric orangeade, while it activated in response to the non-caloric drink. The caloric drink was also found to elicit stronger striatal activation than the non-caloric drink. The striatum has been found to respond to carbohydrates but not non-caloric sweeteners.

The implications of this study signal a need for more research into the effectiveness of non-caloric sweeteners (diet and some sugar free foods) in decreasing overall calorie consumption. In light of the updated 2010 Dietary Guidelines for Americans, this study supports the notion of drinking water instead of sugary drinks as well as enjoying your food but eating less. Satisfying your sweet tooth may very well be linked with the activation of the amygdala. SupermarketGuru encourages you to stick to real foods and ingredients that you can read and understand, as well as smaller portions and occasional indulgences- this is sure to satisfy!

P.A.M. Smeets, P. Weijzen, C. de Graaf, M.A. Viergever: NeuroImage. V 54, I2, Pp 1367-1374, “Consumption of caloric and non-caloric versions of a soft drink differentially affects brain activation during tasting”