Sweetened Beverages and Food Intake
Condition: Overweight; Obesity
MeSH terms: Overweight
Study type: Interventional

Summary: 
      The purpose of this study is to investigate whether beverages sweetened with fructose promote
      overconsumption of calories as compared to beverages sweetened with glucose or a non-caloric
      sweetener.
    

Detailed description: 
      The rise in the prevalence of obesity and type 2 diabetes mellitus has been linked to an
      increased consumption of sugar- and particularly fructose-sweetened beverages. Preliminary
      evidence suggests that this could be partly explained by the fact that the reduction in the
      intake of solid food is inadequate to compensate for additional energy taken up from these
      beverages. In addition, the type of sugar used to sweeten a beverage might have a
      considerable impact on the body's ability to adjust food intake properly. In particular, the
      consumption of fructose has been reported to reduce diurnal plasma glucose, insulin, and
      leptin concentrations, but increase diurnal ghrelin concentrations as compared to isocaloric
      amounts of glucose. As the plasma concentrations of glucose, insulin, leptin, and ghrelin are
      involved in the regulation of food intake and energy expenditure, this might impair the
      longer-term ability of the body to match food intake and energy expenditure to stabilize body
      weight.

      To investigate whether the regular consumption of fructose-sweetened beverages leads to an
      increase in total energy intake, the investigators will enroll healthy normal-weight subjects
      into a controlled diet study using a double-blind randomized cross-over design. Each subject
      will complete three diet periods: solid food plus a beverage sweetened with fructose (A),
      solid food plus a beverage sweetened with glucose (B), solid food plus a beverage sweetened
      with a non-caloric sweetener (C). During each period, subjects will be provided with all
      their food for 8 days. These diets will consist of meals freshly prepared using regular food
      items typically found in the American diet. Solid food will be provided in excess of what the
      subjects are estimated to require. Subjects will be asked to eat as much of this food as they
      need to feel comfortably satiated, and to return all excess foods to the Nutrition Research
      Kitchen of the University of Washington (UW) General Clinical Research Center (GCRC). This
      returned food will be weighed to assess precisely the amount and type of food eaten by the
      subjects on each day of these diet periods. In addition to this solid food, subjects will be
      asked to drink a certain amount of a lemonade sweetened with either fructose (A), glucose
      (B), or a non-caloric sweetener (C). In groups A and B, the subjects will consume 25% of
      their estimated daily calorie requirement in the form of these sugar sweetened beverages,
      while the drink in period C will be of the same volume.

      Subjects will be admitted to the GCRC on the morning of day 9 of each diet period for the
      measurement of resting metabolic rate by means of indirect calorimetry and blood draws for
      the measurement of fasting plasma concentrations of adipogenic hormones and plasma lipids.
      Furthermore, we will administer a standardized breakfast and draw blood before and 0, 15, 30,
      60, 90, and 120 minutes after this meal to measure the postprandial plasma concentrations of
      insulin, ghrelin, and satiety signals. Following the last postprandial blood draw, we will
      serve another meal to measure ad libitum food intake. Our hypothesis is that subjects will
      have more appetite and consume more food after they have consumed the fructose-sweetened
      beverage for 8 days.

      Primary outcome measures of this study will be the total energy consumed during the periods
      A, B, and C; the reduction in the intake of solid foods in periods A and B as compared to
      period C; and energy uptake during the ad libitum meal served on day 9 of each diet period.
      Secondary outcome measures will be resting energy expenditure and plasma concentrations of
      satiety and adiposity signals.
    

Intervention name(s): Fructose; glucose; non-caloric sweetener
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): 25% of energy intake in the form of a fructose-sweetened beverage (arm 1), a glucose-sweetened beverage (arm 2), or an isovolumetric amount of a beverage sweetened with a non-caloric sweetener; 25% of energy intake in the form of a fructose-sweetened beverage (arm 1), a glucose-sweetened beverage (arm 2), or an isovolumetric amount of a beverage sweetened with a non-caloric sweetener; 25% of energy intake in the form of a fructose-sweetened beverage (arm 1), a glucose-sweetened beverage (arm 2), or an isovolumetric amount of a beverage sweetened with a non-caloric sweetener
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: Overweight; Obesity; Appetite; Dietary sugars; Fructose; Glucose; Leptin; Insulin; Ghrelin