Effect of reducing portion size on energy intake and appetite

Recruitment & Eligibility

Status: Completed

Sex: All

Target Recruitment: 33

Inclusion Criteria

Healthy 18-60 year old men and women with a BMI of 25-35 kg/m^2

Exclusion Criteria

1. Eating disorders assessed using the Eating Attitudes Test (EAT) score =11 (measured at a screening visit)
2. Depression using the Zung Depression Scale score =70 (measured at a screening visit)
3. Smoking
4. Excessive habitual alcohol intake (>14 units per week for women and >21 units per week for men)
5. Weight loss or gain within the last 3 months or actively trying to lose or gain weight (more than 4.5kg)
6. Medications affecting food intake and metabolic responses (insulin, weight loss medications, laxatives, selective serotonin reuptake inhibitors (SSRIs), oral hypoglycaemic drugs, oral corticosteroids), thyroxine and drugs acting on the sympathicomimetic system and drugs affecting gastrointestinal motility
7. Diagnosed psychiatric disorders controlled pharmacologically
8. Acute and chronic inflammatory conditions (i.e., cold, flu, inflammatory bowel disorders and coeliac disease)
9. Diabetes or fasting glucose <7 mmol/l (measured at a screening vist)
10. Any other medical condition or medications having a potential effect on regulation of appetite (i.e. neurodegenerative disorders, malignant cancer, liver diseases or severe anaemia).
11. Pregnancy, breastfeeding or planning a pregnancy
12. Athletic training
13. Allergies to, restriction or dislike of any test foods to be used, including vegetarians/vegans
14. Not regular breakfast consumers (classified as those consuming breakfast less than or equal to 3 times per week)

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Energy intake at lunch measured by an ad libitum lunch meal 4 hours after breakfast.

Secondary Outcome Measures

Name	Time	Method
1. Energy intake over the rest of the day measured at an ad libitum snack 6 hours after breakfast and by a weighed diet diary over the rest of the day.<br>2. Appetite (hunger, fullness, desire to eat and prospective consumption) measured using visual analogue scale (VAS) questionnaires before and after breakfast and lunch, at half hourly intervals between breakfast and lunch and then at hourly intervals for the rest of the day.<br>3. Perceived portion size of the breakfast meal measured using VAS questionnaires during the breakfast meal.<br>4. Biochemical measures of appetite (glucose, insulin, peptide tyrosine tyrosine (PYY), glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP)) measured in the blood at fasting, and 30, 60, 120, 180 and 240 minutes after breakfast.