A person’s mindset or outlook influences his/her taste and choice of food. Food labels have been shown to shape one’s sense of fullness. Studies have revealed that when people consume food marked as “high-calorie,” their satiety is more and their subsequent food consumption is less. In a recent study, the researchers wanted to confirm these findings by measuring the level of the hormone ghrelin in blood. The results showed that “participants’ satiety was consistent with what they believed they were consuming rather than the actual nutritional value of what they consumed.”
Ghrelin is a hormone produced in the stomach when the body’s energy level is low. It acts on the brain and induces hunger pangs in order to motivate food consumption. Once food is consumed, the levels of ghrelin drop, thereby producing a sense of satisfaction. This study examined whether the mindset of an individual affects the feeling of satisfaction after consuming food. Volunteers for the study were asked to consume milkshakes on two occasions. These milkshakes were similar in all aspects except their labels; one was labeled “high-calorie” while the other was labeled “low-calorie”. After drinking the milkshakes, the subjects were tested for levels of ghrelin in their blood.
* The study included 46 participants aged between 18 and 35 years with normal or marginally high body weight. They underwent two sessions of tasting milkshakes just one week apart. They were told that the aim of the study was to assess the tastes of two different milkshakes.
* During each session, each participant was given a different milkshake and was asked to study and rate the label of the milkshake and to drink and rate the taste of the milkshake. In reality, the milkshakes given during both the sessions were identical; however, they were labeled to indicate either high-calorie or low-calorie content.
* During the sessions, blood was collected after 20 minutes, 60 minutes and 90 minutes for assessment of ghrelin levels. After drawing blood each time, the participants’ perception of hunger was estimated by using a questionnaire.
* They were also asked to rate the drinks based on smell, look, and sense of satisfaction.
* The milkshake labeled “sensible” (low-calorie) was rated to be healthier than the high-calorie “indulgence” milkshake.
* With the “indulgence” shake, the ghrelin level rose markedly in anticipation of the rich food and fell sharply after its consumption, indicating high satiety.
* In the case of the “sensible” shake, the rise in the level of ghrelin was less before consumption and later, its drop was less, indicating poor satiety.
* “The observed pattern of ghrelin response is consistent with what one might observe if participants actually consumed beverages with different calorie contents.”
This study has identified that apart from the actual calorie content, the mindset of a person also determines the subsequent calorie consumption. However, this study has not examined the long-term effects of such changes in mindsets. Further studies to analyze the relationship between consumption of foods with different depicted calorie contents and changes in the body weights of participants are warranted. By such studies, the effect of mindset on the development of obesity can be determined.
The present study has highlighted that if a food is labeled “low-calorie”, the levels of ghrelin do not rise as expected, indicating that the person is not physiologically satisfied. In such cases, people tend to consume more food and are hence at risk of developing obesity. Many companies sell their food items with labels such as low- or no-fat. If these items contain the usual amount of fat, people consuming them will be prone to develop obesity. At present, there are studies being conducted to assess the utility of gut hormones like ghrelin in the treatment of obesity. The fact that the mind controls the release of these hormones must be taken into consideration before actual treatment by these hormones is started.
For More Information:
Mind over Milkshakes: Mindsets, Not Just Nutrients, Determine Ghrelin Response
Publication Journal: Health Psychology, May 2011
By Alia J Crum; William R Corbin
From the Yale University, New Haven, Connecticut, and Arizona State University, Phoenix, Arizona
*FYI Living Lab Reports Are Summaries of the Original Research.