The Effect of Dietary Fibre and Plant Protein on Appetite and Metabolic Function

The Combined Effect of Dietary Fibre and Plant Protein on Appetite and Metabolic Function After Short-Term Consumption

Acute effects on appetite and metabolic function have been observed for whole-grain rye cereal products. The aim of this study is to evaluate if the appetite suppressing effect of a whole-grain rye breakfast cereal may be further enhanced by the addition of fermentable dietary fibre and plant protein. The aim is also to try to elucidate how observed effects on subjective appetite are mediated in terms of changes in hormonal signals, flow of nutrients in the blood and products from bacterial fermentation of dietary fibre, and to relate this to the different composition of the breakfasts.

The short-term effects (up to 8 hours after intake) of dietary fibre and plant protein on subjective appetite and metabolism will be evaluated using a randomized cross-over study design. Each participant will consume six different breakfasts on six different occasions separated by a 1 week wash-out period: three rye porridges supplemented with three different combinations of added fermentable dietary fibre and plant protein, two non-supplemented rye porridges differing in amount of rye and one wheat bread. Participants will rate subjective appetite (satiety, hunger and desire to eat) by using a visual analog scale (VAS) every 30 min during an 8-hour period, starting 30 min before breakfast. The concentration of hydrogen and methane in the breath, as indicators of bacterial fermentation of dietary fibre, will be measured every hour. Blood samples will be collected before breakfast and at regular intervals throughout the day for analysis of glucose and hormone levels. The metabolic profile in the blood will be assessed as well as products from bacterial fermentation of dietary fibre, such as short chain fatty acids. Gastric emptying rate will also be evaluated using paracetamol as an indicator. Hormonal responses, changes in the metabolome and fermentation products will be related to subjective appetite and to differences in composition of the breakfasts.

Inclusion Criteria:

• Women must be post-menopausal or habitually take hormonal contraceptives
• Habitual breakfast eaters

Exclusion Criteria:

• Non-contraceptive use among pre-menopausal women
• Pregnancy, lactation or wishing to become pregnant during the study period
• Dieting
• Weightloss
• Eating disorder
• Hyperglycemic
• Hyperinsulinemic
• Thyroid disease
• Metabolic issues
• Diabetes
• Physical or psychological problems eating
• Food intolerances/allergies to foods included in the study
• Vegetarians
• Intolerance/allergy to paracetamol
• Heavy smokers
• Recent or concurrent participation in an intervention research study