Effects of Food Form and Fitness on Appetite and Digestion.
Condition: High and Increasing Contribution of Energy From Beverages in the Diet May Enhance Positive Energy Balance and Weight Gain
MeSH terms: Weight Gain
Study type: Interventional

Summary: 
      Energy-yielding fluids induce weaker appetitive and compensatory dietary responses than
      energy-matched semi-solids or solids. This is problematic because the high and increasing
      contribution of energy from beverages in the diet may enhance positive energy balance and
      weight gain. The prevailing view of the overweight/obesity problem is that it stems from a
      small, sustained positive energy balance. It follows then that only small changes, perhaps
      manipulations in the rheological characteristics of the diet, will be required to correct the
      problem. Certain populations that are more prone to weight gain may benefit from such
      manipulations. Obese individuals have a higher beverage intake and experience greater weight
      loss with reductions in beverage intake. Further, there is evidence that obese individuals
      consume more energy after a liquid pre-load than their lean counterparts, yet there is no
      difference in energy intake after a solid load. In contrast, habitual exercisers have been
      shown to have an increased accuracy of short-term regulation of food intake at meals
      following liquid preloads. A better understanding of the mechanisms by which beverages and
      energy-matched solid food forms elicit differential appetitive and dietary responses in these
      populations needed. This research will attempt to identify the influence of physical fitness
      and body fat on the ability to compensate for the energy content of solid and liquid preloads
      by reduction in energy intake at a subsequent ad libitum meal (i.e., acute compensation) and
      over the course of the day (i.e., short-term compensation). Furthermore, this study will
      examine the cognitive contribution to differential responses to energy-matched beverage and
      solid food forms and the effects of mastication on appetite, GI transit, glycemic response,
      and selected endocrine responses.
    


Intervention name(s): liquid to liquid; liquid to solid; solid to liquid; solid to solid
Intervention type(s): Behavioral; Behavioral; Behavioral; Behavioral
Intervention description(s): • One test session will involve presentation of a glass of clear cherry-flavored unthickened beverage (Kool-Aid, Kraft Foods Inc., White Plains, NY). This session will be referred to as the "Liquid to Liquid" session as the participants will be consuming a liquid and be told that the consistency in their stomach will be a liquid.; This session involves a solution of calcium chloride and a solution of sodium alginate. The participant will be instructed to pour the cherry-flavored beverage/alginate solution into the calcium chloride. The result is a solid mass. They are allowed to examine the solution to confirm the solid texture and consistency.Participants will be told that this same reaction will occur in their stomach when the session's beverage is consumed due to the effect of gastric acid on the solution. But, the participant will be consuming the same cherry-flavored beverage as in the 1st session. Thus, they will believe that their GI tract will be challenged with a solid mass, but in reality, the challenge is the same (i.e., liquid).Therefore, the only difference between the test sessions is expectation.; • This session will involve the same dense gelatin cubes previously described, but participants will be told that the solid cubes will turn to liquid when they come into contact with the acid in their stomach. This trial will be known as "Solid to Liquid". A demonstration of the "Solid to Solid" and "Solid to Liquid" phases will be shown to the participant before they consume the load. Both phases exhibited by placing two cubes into separate containers filled with similar looking clear liquids. The "Solid to Solid" phase container will contain cold water so the cube stays in solid form. The "Solid to Liquid" phase container will contain hot water that will quickly dissolve the cube into a liquid form.; Participants will be presented with dense gelatin cubes. These 1" x 1" x 1" cubes will have a solid appearance and require mastication, but is isocaloric to the beverage. However, after mastication and gastric processing, the solid rapidly breaks down into a clear fluid.However, participants will be informed that the cubes will remain the same solid consistency in their stomach. The masticatory process and stimulus form will be standardized through the use of a metronome. Participants will be required to chew the solid cube at a fixed rate prior to swallowing. Thus, adding to the cognitive impression that they are eating a solid when essentially the GI challenge will be similar to the beverage.
Other intervention name(s): Liquid test load; liquid test load; liquid test load; liquid test load
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: obese, liquid, solid, fitness, humans, appetite