Impact of a Satiating Diet in Obese Men With a Low Satiety Phenotype
Condition: Obesity; Appetite Disorders
MeSH terms: Obesity; Feeding and Eating Disorders
Study type: Interventional

Summary: 
      The global research project was organized as a clinical process starting with an evaluation
      aiming at the determination of a diagnosis pertaining to the degree of satiety signal
      capacity. It was extended by a phase of metabolic and behavioural characterization to better
      understand the clinical condition of the patients. The main part of the program was a weight
      loss intervention that was focused on high satiating foods. Finally, the process was
      completed by an evaluation allowing to determine the impact of the intervention on the
      metabolic and behavioural conditions of the patients.
    

Detailed description: 
      Dietary restriction, being prescribed as low and very low calorie diets, has been largely
      used as a strategy of dietary management of obesity. Beyond the fact that these diets fully
      respect the first law of thermodynamics, they are also rather easy to supervise and they
      offer a guarantee of substantial weight loss to compliant patients. Dietary restriction
      strategies also carry important limitations which include their failure to take into account
      appetite sensations of the obese patient. This point is important since it dictates the
      extent to which the patient can tolerate his/her dietary regimen without hunger over time as
      well as its related body weight loss. In this regard, experimental and clinical data show
      that weight regain up to initial body weight and even more occurs over years after a
      diet-induced weight loss. Moreover, evidence also revealed that restraint behaviour is
      difficult to maintain over time and that a decrease in this behaviour is related to weight
      gain on a long term basis. The challenge thus becomes the search of a strategy that can
      promote a substantial spontaneous energy deficit without significantly altering hunger and
      satiety levels as well as their related well-being. Up to now, the only approach which
      emerges as having the potential to respect these two criteria is the design of functional
      foods, i.e. foods with sufficient satiety-promoting properties to compensate for the
      enhancing effect of body fat loss on appetite. The food specialists can rely on a catalogue
      of functional ingredients that can be used to prepare functional menus in order to improve
      the regulation of energy balance and body weight stability in individuals prone to obesity.
      As described above, this issue would be particularly relevant for obese individuals
      displaying a low satiety phenotype, i.e. individuals experiencing difficulty to match energy
      intake to expenditure in a context promoting excess food intake.

      The objectives of this study were to characterize obese men displaying the low satiety
      phenotype (metabolic and behavioral characteristics) and to determine the impact of highly
      satiating foods on body weight loss, satiety feelings and compliance in this population.

      EXPERIMENTAL DESIGN

      Recruitment of subjects and satiety phenotype determination

      Each patient referred by a physician was contacted by phone and a first screening interview
      was performed to validate the inclusion criteria. After recruitment, every subject was met to
      read and sign the letter of consent as well as to discuss every aspect of the program about
      which he might have some questions. We took advantage of this brief meeting to measure
      height, body weight and waist circumference to determine BMI and to estimate the level of
      abdominal fat.

      This phase also included a 2-hour session of evaluation in order to determine satiety signal
      capacity (SQ). At the end of this session, each subject completed the Three-Factor Eating
      Questionnaire with the specific preoccupation to measure cognitive dietary restraint as an
      exclusion criterion. The information collected in this first phase of testing was used to
      subsequently classify subjects on the basis of their satiety signal capacity (low SQ vs
      normal/high SQ). Subjects not selected to participate in the next phase of the project
      received, in addition to their health report, a free dietary consultation focusing on the
      adoption of healthy behaviours. This first phase of testing allowed to rank order subjects on
      the basis of their score obtained with the satiety quotient. Seventy participants were
      selected to participate in the study

      Initial metabolic and behavioural characterization (Time 0)

      This phase of testing began by a standard medical examination performed by the physician of
      our research team several days before the main testing session. This permitted to identify
      potential illnesses influencing appetite control and to evaluate the general health condition
      of each subject. In order to evaluate the reproducibility over time of the satiety quotient
      determination and to ascertain the status of subjects determined at the initial evaluation,
      the standardized breakfast test meal was repeated. However, this test was performed in a
      session of longer duration that allowed to characterize metabolic and behavioural factors
      associated with a low/high satiety capacity. The measurements included in this phase of
      testing were used as baseline measurements for the next phase of this project.

      Intervention study

      The 70 participants were randomly assigned to either a weight loss program consisting of a
      highly satiating diet (n=35) (low to moderate in fat (30-35%), high in fibres (> 25g/day),
      high protein (20-25% of total energy intake) and including 45-50% energy as carbohydrate
      mainly provided by foods with low glycemic index and adequate to slightly increased vitamin
      and mineral intakes) which is expected to induce a spontaneous energy deficit or a diet
      supervision based on the guidelines concordant with the Canadian Food Guide (n=35) (10-15,
      55-60 and 30% energy as protein, carbohydrate, and lipid, respectively). For statistical
      analysis, 4 subgroups have been created based on the SQ classification: 1) low SQ, high
      satiating diet 2) low SQ, conventional healthy diet, 3) normal/high SQ, high satiating diet,
      4) normal/high SQ, conventional healthy diet. This experimental environment thus corresponded
      to a two by two factorial design in which the two independent variables are SQ and diet.
      Participants were encouraged to comply with the diets for a 16-week period even if a
      resistance to weight loss (i.e weight maintenance during one month) was observed during the
      protocol.

      Final metabolic and behavioural characterization (Post-tests; week 16)

      All the measurements performed at Time 0 were repeated immediately after the 16-week
      intervention period for each of the four subgroups of subjects.

      POTENTIAL OUTCOME AND FUTURE PERSPECTIVES

      The main conceptual outcomes of this were: 1) the characterization of factors implicated in
      different satiety signal capacities; 2) the investigation of the role of individual capacity
      of satiety signal in body weight loss and diet compliance, and 3) the determination of the
      impact of functional menus promoting satiety to compensate for the low spontaneous satiety
      level in some obese individuals. In addition, this project provided clinical and economical
      outcomes. Indeed, it represented the first study documenting the weight-reducing impact of a
      healthy diet based on foods whose functionality have been upgraded by food design. If this
      project confirms that such a diet can promote weight loss without restriction, but while
      rather being associated with well-being, this will be a major gain for clinical nutritionists
      who have up to now unsuccessfully try to counteract the obesity epidemic and who have to deal
      with consumers who primarily request palatable foods instead of a priori focusing on healthy
      food. From an economical standpoint, this program will be a reference source of validation
      for the industry seeking justifications and claims to promote healthy foods facilitating body
      weight control.
    

Intervention name(s): Satiating diet; Control diet
Intervention type(s): Behavioral; Behavioral
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: Obesity; Satiety quotient; Appetite control; Weight loss; Satiety phenotype; Functional food