Appetite Ratings, Postprandial Glucose, Insulin and Gastrointestinal Hormone Responses After the Intake of an Enriched Fiber and Protein Breakfast Soft Bread in Healthy Adults

A total of 30 healthy adults (17 males and 13 females) ranging from 19 to 32 years old (mean age 25 ± 1), with a body mass index (BMI) ranging from 19.2 to 28.5 (mean BMI 23.3 ± 0.5) (normal to moderately overweight) participated in this study. To avoid the risk of reaching false conclusions, psychometric validations of food restrictions were determined for all subjects using the revised version of the Three Factor Eating Questionnaire.

This study was carried out according to EFSA requirements [Blundell et al., 2010]. The subjects were instructed to refrain from alcohol and/or from performing difficult physical activities 48 h prior to each test day. The evening before the test day, the subjects consumed a standardised dinner supplied by the study team. The meal consisted of pizza and pineapple juice (800 kcal: protein 18%E, fat 22%E and carbohydrate 60%E). The subjects were instructed to not eat or drink anything other than half a litre of water after the dinner.

After 20 min of resting, on the first day of intervention, anthropometric measurements (weight, height and waist circumference) were collected on subjects wearing only underwear and after emptying their bladder. On each day of the study, a fasting blood sample was acquired after the resting time, and appetites were assessed with a visual analogue scale (VAS).

The subjects were instructed to consume the tested breakfast (the soft roll bread or the control bread plus jam and margarine) within 10 min and were allowed to drink 150 ml of water. The subjects immediately completed two VASs, one on meal palatability and another on appetite feelings. In addition, the appetite feeling VAS was repeated every 30 min until a total of 4 h had passed.

The subjects were not allowed to eat or drink anything else during the 4 h of the intervention. They were allowed to read, study, talk or listen to quiet music, but they were not allowed to sleep. After the last blood extraction (4 h), an ad libitum lunch consisting of a standardised spaghetti Bolognese (17%E protein, 34%E fat and 49%E carbohydrate) and water (300 ml) was provided. The subjects were instructed to eat until comfortably satisfied. Food intake was registered by differences in spaghetti weight before and after lunch, and the energy intake was calculated afterwards. After the ad libitum lunch, the subjects completed two VASs, one on meal palatability and another on appetite feelings. The participants completed a 48-h dietary survey diary, including the food intake during the day before and the day of the intervention.