(Mis)Perceptions About Healthy Eating: Effects on Food Intake and Appetite in Men and Women
Condition: Eating; Obesity
Study type: Interventional

Summary: 
      In the face of an increased prevalence of obesity and chronic diseases in Canada, much effort
      has been invested to educate the population about healthy eating. Although Canadians are now
      aware of the importance of healthier food habits, rates of obesity and chronic diseases are
      still increasing. In addition, even if different labelling strategies are used to identify
      healthier foods in the market, consumers remain confused about what healthy eating should be.
      Might describing foods as healthy have unintended side-effects on food intake? Previous
      literature has shown that perceptions about the healthiness of foods may bias estimations of
      caloric content of foods, leading consumers to underestimate the caloric content of "healthy"
      food choices. Indeed, the investigators have recently shown that perceiving a food as healthy
      increased intake of that food by 35% in undergraduate female students. The general objective
      of the proposed research is to investigate whether food perceptions influence intake and
      appetite sensations in normal-weight and overweight/obese restrained and unrestrained males
      and females. This laboratory study, in which perceived healthiness and "fatteningness" of
      oatmeal-raisin cookies will be manipulated during an ad libitum single-meal occasion, will
      increase the investigators knowledge of the effects of external cues (and other psychological
      and physiological factors) on the control of food intake. Because the popularity and demand
      for nutrition information is increasing, such information is needed to improve clinical
      practices aiming at promoting sustainable healthy eating habits to help individuals achieve
      and maintain a healthy weight.
    

Detailed description: 
      The laboratory study will be conducted at the Clinical Investigation Unit (CIU) of the
      Institute of Nutraceuticals and Functional Foods (INAF). Food-related variables (perceived
      healthiness and "fatteningness" of foods) will be manipulated during an ad libitum
      single-meal test. We will examine the effects of these variables on food intake and appetite
      sensations in male and female normal-weight and overweight/obese restrained and unrestrained
      eaters. Each participant will be tested on an individual basis, during a 2-hour experimental
      session (randomized sessions between 11:00 a.m. and 5:00 p.m.). Because participants might
      change their eating behaviors if they become aware of the true purpose of the study,
      deception must be used. Males and females will thus be recruited to participate in an
      ostensible market-research study involving a taste-rating task, and each participant will
      then be carefully debriefed at the end of the experiment.

      Male and female normal-weight with a body mass index (BMI) ≥18.5kg/m2 and <25kg/m2 and
      overweight/obese with a BMI ≥25kg/m2, restrained and unrestrained eaters will be randomly
      assigned to one of three experimental conditions ("healthy," "diet," and "unhealthy"). A
      plate of about 1000 grams (g) of bite-sized oatmeal-raisin cookies will be presented to each
      participant. On average, one bite-size cookie is about 10g, which represents approximately 40
      kilocalories (kcal) per cookie. The manipulation of healthiness and "fatteningness"
      perceptions of the oatmeal-raisin cookies will be performed verbally by the experimenter as
      follows. In the "healthy" condition, the description will emphasize nutritional
      characteristics (e.g., high in fibre, low in saturated fat and free from trans-fat), so the
      overall healthiness of the snack will be highlighted. In the "diet" condition, the
      description will emphasize the benefits of oatmeal fibre for weight management (e.g., helps
      to cope with hunger), thereby highlighting the weight-loss potential of the snack. In the
      "unhealthy" condition, the description will emphasize hedonic characteristics of the food and
      less healthy ingredients (e.g. gourmet cookies, contains butter and sugar), so some inherent
      unhealthy aspects of the snack will be highlighted.

      Males and females involved in the study will be invited to participate in a market-research
      study investigating various dimensions of a new snack product. A telephone screening
      interview will first be conducted for all subjects interested in participating in the study
      to ensure that they meet our inclusion criteria, to facilitate randomization prior to the
      experiment session and to set the appointment with the participant. During this interview,
      each participant will be informed that this market-research study involves a taste-rating
      task in which they will taste and rate a new snack food. They will have to self-report their
      weight and height, and answer descriptive questions about inclusion criteria (e.g., history
      of health problems, current medications, liking of the tested food, and prior participation
      in studies). They will also have to complete the Restraint Scale to assess whether they
      exhibit behavioral and attitudinal concerns about dieting and weight control. Each
      participant will then be categorized as a restrained eater (≥12 in males and ≥15 in females)
      or unrestrained eater (<12 in males and <15 in females). Following the categorization
      established by the Restraint Scale and BMI calculation, each participant will then be
      randomly assigned to one of the experimental conditions, according to restraint and weight
      status (Note that randomization will be adjusted according to the measured BMI). The
      telephone screening interview will be conducted at least one week prior to the appointment at
      the CIU to ensure that having been asked about restraint and weight status will not affect
      participants' food intake and appetite sensations by making restraint and weight salient
      during the experiment. To standardize food intake and to insure that subjects have comparable
      baseline appetite sensations across experimental manipulations, participants will be asked to
      refrain from eating oatmeal-raisin cookies (tested food) for at least 24 hours prior to the
      experiment, and to arrive at the CIU for the appointment in a pre-meal state (i.e., at least
      2 hours without food prior to the experiment). Because physical activity might have an impact
      on appetite sensations, participants will also be asked to refrain from doing any strenuous
      exercise at least for 24 hours before the experiment. Note that the experimenter in the study
      will strictly follow a detailed script when testing each participant to ensure that the
      testing will be consistent between all participants.
    

Intervention name(s): Healthy; Diet; Unhealthy
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): Favourable nutritional characteristics.; Benefits of an ingredient/nutrient for weight management; Hedonic characteristics and less healthy ingredients.
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: Single (Participant)