Impact of Cognitive Dietary Restraint on Perceived Stress, Appetite Sensations, Food Cravings During Energy Restriction
Condition: Overweight
MeSH terms: Overweight
Study type: Interventional

Summary: 
      The purpose of this study is to measure the effects of a reduced-calorie low energy density
      diet with and without increased cognitive dietary restraint (CDR) on stress (biological
      markers and perceived stress), eating behaviours, appetite sensations, anthropometric
      variables and women's attitude toward their children's eating behaviours in premenopausal
      overweight/obese women in both the short term (immediately after the end of the 4-week
      intervention) and longer term (3 months after the end of the intervention). The investigators
      hypothesize that cortisol concentrations are higher, appetite sensations are increased (i.e.
      increased global appetite score) and food cravings are more prevalent in women of the
      energy-restriction-plus-CDR group than in women of the energy-restriction-without-CDR group
      after the 4-week intervention. They also hypothesize that perceived stress is higher and food
      cravings are more prevalent in women of the energy-restriction-plus-CDR group than in women
      of the energy-restriction-without-CDR group at 3-month post intervention. They hypothesize
      that no significant difference in body weight changes is observed between the two groups and
      that maternal restriction of their child's eating is higher in the
      energy-restriction-plus-CDR group than in the energy-restriction-without-CDR group both after
      the 4-week intervention and at the 3-month follow-up.
    

Detailed description: 
      It is clear that a large proportion of individuals regain weight following dietary weight
      loss interventions most likely because of homeostatic and non-homeostatic factors favouring a
      return to initial energy status. However, studies performed to date have documented these
      effects in the context of interventions favouring both energy restriction and CDR. Thus, the
      difference between a state of energy restriction alone and a state of energy restriction
      combined to CDR on factors regulating energy balance is not known. In order to study this
      important question appropriately, we need to create a condition of energy restriction without
      increasing CDR, which can only be achieved with a satiating diet (i.e. well-balanced low
      energy density diet). This is easier to create in the context of a controlled intervention in
      which all foods and drinks are provided. We propose to create, in a controlled context, an
      energy restriction for which subjects will be blinded i.e. they will consume less energy than
      their energy needs without knowing that they are restrained. Such a design will permit to
      document for the first time the independent effects of CDR in the context of a reduced
      calorie diet on factors associated with the regulation of energy balance. The proposed study
      will also allow exploring the impact of increasing CDR on women's attitude toward their
      children's eating behaviours. Taken all together, results arising from the proposed study
      will better position the relevance of developing weight loss approaches not focusing on CDR
      to favour healthy weight management for women and their family. Data will be collected before
      and after the 4-week intervention, as well as 3 months after the end of the intervention. In
      order to appropriately test our hypotheses, we cannot state the real purpose of the study in
      the informed consent form and women will be told that it is a study about the impact of diet
      on blood pressure. However, at the end of the study, women will be debriefed and will sign a
      second informed consent form in which the true purpose of the study will be explained.
    

Intervention name(s): Energy restriction plus CDR; Energy restriction without CDR
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Subjects will receive a reduced-calorie low energy density diet which will provide 85% of their energy needs for a period of 4 weeks. In the condition in which an increase in CDR will be induced, women will be told at the beginning of the study and will be reminded throughout the 4-week duration of the experimental condition that they are on a low-calorie diet and that it is important not to eat more than what is provided and that they should strictly avoid non-study food if they want to lose weight and improve their blood pressure. Subjects will receive feedback about their weight trajectory. After the 4-week controlled intervention women will then receive further information and advices to pursue their weight loss on their own and keeping on with strategies relying on an increase in CDR.; Subjects will receive the same low-calorie diet (85% of their energy needs) for 4 weeks but will not be told that they are on an energy-deficit diet. They will be told at the beginning of the study that the food provided cover all their nutrient needs and that they should eat until satiation. There will be no emphasis on body weight and subjects will be reminded that the aim of the intervention is to document the effects of a diet rich in vegetables and fruits on blood pressure. After the 4-week controlled diet, participants will be taught about the impact of a low energy density diet on satiation and satiety. They will receive further information and advices (with non-restrictive messages) to incorporate more vegetables and fruits in their usual diet.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: Women; Caloric restriction; Cognitive dietary restraint; Eating behaviours; Food habits; Appetite sensations; Stress; Weight management