Placebo Breakfast Consumption, Appetite and Food Intake
Placebo Breakfast Consumption, Appetite and Food Intake
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.
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.
Inclusion Criteria:

 -  Non-smoker.

 -  Habitually consuming breakfast at least 3 days per week.

 -  Have maintained a stable weight for 6 months (self-reported).

 -  No known history of gastric, digestive, cardiovascular or renal disease.

 Exclusion Criteria:

 -  Food allergies, dislike or intolerance of study foods or drinks.

 -  Not currently on a weight management program or have irregular eating patterns (i.e.
 extended fasting periods >8h other than overnight - self reported).

 -  Use of medication that may affect hormone concentrations.

 -  Excessive alcohol consumption (>4 units/day).

 -  Intensive training schedule (>10 hours/week).