Placebo Breakfast Consumption, Appetite and Food Intake
Condition: Obesity
Study type: Interventional

Summary: 
      The purpose of this study was to examine the effects of a very low-energy, viscous placebo
      breakfast meal on subjective appetite sensations during the morning, and food intake at
      lunch, compared to a typical whole-food breakfast meal and a water-only control. Participants
      will not be told that the placebo breakfast contains nearly no energy until the end of the
      study. The breakfasts will be provided in a randomised order, with a period of at least four
      days separating the trials. Blood samples will be taken before and after the breakfast is
      eaten to see how appetite-regulating proteins and blood sugars respond during the morning.
      Appetite questionnaires will also be completed throughout the morning, and a pasta-based
      lunch meal will be provided so that voluntary food intake can be measured.
    

Detailed description: 
      Obesity is a risk factor for several chronic diseases, including type-2 diabetes, heart
      disease and some forms of cancer. There is clear evidence demonstrating that weight gain
      occurs progressively over the lifespan, highlighting that preventative action should be taken
      by young, lean individuals, who may yet develop overweight or obesity later in life. A
      positive energy imbalance, in which energy intake exceeds energy expenditure for a sustained
      duration, is known to be the underlying systematic cause of obesity. Therefore, reducing
      daily energy intake is a seemingly simple solution to the this problem. However, compensatory
      alterations in appetite regulation which stimulate an increase in energy intake often impede
      the long-term success of such interventions.

      Extending the overnight fasting period, thereby restricting the time available for food
      intake, has emerged as an effective dietary strategy for reducing daily energy intake and may
      assist with weight management. Laboratory studies have shown that skipping breakfast
      typically results in increased appetite during the morning, and an increase in energy intake
      at lunch. Therefore, the long-term success of skipping breakfast may be reduced by elevated
      appetite sensations. A recent study which aimed to assess the effects of a very-low energy,
      placebo breakfast on resistance exercise performance noted that appetite was suppressed after
      consuming the placebo, despite its lack of energy content. Whether this suppression of
      appetite following placebo breakfast consumption results in a reduced energy intake at lunch,
      is currently unknown. Therefore, the investigators are interested to examine the subjective
      and hormonal appetite responses to placebo breakfast consumption, compared with these
      responses to an overt breakfast consumption trial an overt breakfast skipping trial, and
      whether these changes result in any differences in voluntary energy intake at lunch.

      The present study is a randomised, controlled, crossover study in which fourteen healthy,
      habitual breakfast-consuming (self-reported) males will consume a very low-energy, viscous
      placebo breakfast, a typically consumed, whole-food breakfast, and a water-only control. At
      least four days will separate trials.

      Participants will firstly complete a pre-screening session in which anthropometric data will
      be collected. This will be used to determine the energy content of the typical whole-food
      breakfast.
    

Intervention name(s): Placebo breakfast; Typical whole-food breakfast; Water-only control
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Participants will consume a very low-energy, placebo breakfast meal, but will be unaware of its near complete absence of energy until the end of the study.; Participants will consume a typical whole-food breakfast meal, equating to 20% of estimated energy requirements.; Participants will consume a volume of plain water to match the water content of the very low-energy placebo breakfast and the typical whole-food breakfast.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The study design is a randomised, controlled, crossover design in which participants undertake three dietary conditions in a randomised order with at least a four day period in between trials.
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: Breakfast skipping; Energy intake; Energy balance; Appetite hormones; Placebo feeding