Impact of the Eating Rate of Ultra-processed Foods on Dietary Intake Behavior and Metabolic Responses

The average (across two weeks) daily energy intake (kcal/day) in each diet arm

Ad libitum energy intake (kcal) per meal, day and week.

Ad libitum food intake (gram) per meal, day, week and average daily food intake (gram/day) in each diet arm.

Cumulative energy intake (kcal) over the study period (14 days)

Cumulative food intake (gram) over the study period (14 days)

Participant's weight will be measured in duplicate to obtain an average. The participant will be measured in stocking feet and light clothing on a standard balance scale. Participant will not be able to see their weight.

Changes in fat mass and fat free mass (kg, %) will be measured using; DEXA, air displacement plethysmography (BODPOD), skinfold measurements

Insulin and glucose, total ghrelin, total GLP-1, PP, PYY, Glucagon and c-peptide responses, to a fixed calorie test meal (rice porridge)

Resting energy expenditure will be measured 30 minutes before a Mixed Meal Tolerance Test (MMTT) consisting of a fixed energy amount of rice porridge, and 30 minutes immediately after the meal using a ventilated hood. Based on this we will estimate the respiratory quotient, diet induced thermogenesis and substrate use. Based on the resting energy expenditure in combination with physical activity levels (estimated based on accelerometer (actigraphy) and 24hr recalls of exercise/sports) energy expenditure will be calculated per participant.

24-hour glucose levels will be measured using Continuous Glucose Monitoring (CGM). This will be used for a comparison of percentage of time spent within and out of the normative range.

Leptin, Ghrelin blood plasma concentrations after an overnight fast

Total cholesterol, HDL, LDL, free fatty acids and other blood lipids

Total meal duration (min), bite duration (min) and number of bites

Derived measures of eating behaviour such as eating rate (g/min) based on video-annotation.

Chewing behaviour, oro-sensory exposure time, bite size (gram/bite) and bite frequency (bite/min) based on video-annotation.

Eating behaviour characteristics (eating rate (gram/min), total meal duration (min), bite duration (min), bite frequency (bite/min), number of bites (per meal), bite size (gram/bite), oro-sensory exposure time (seconds/bite), cumulative weight change of the meal from start to end, based on weighing tray.

Sensory properties, liking and familiarity of the meals, assessed after one bite of each meal on a 100mm Visual Analogue Scale ranging from "Not at all" (0mm) to "Extremely" (100mm).

Intake of carbohydrates, protein, and fat (gram; %EN) per meal, day, week and study period.

Dietary intake (energy intake, macronutrients, fiber, salt, and UPF) will be measured using a 3 day food diary ( 2 week-days and one weekend day).

Sodium and nitrogen in urine will be measured in urine as markers for salt and protein intake as compliance markers of participants dietary intakes

Untargeted metabolomics, C-peptide, creatinine

Intake of mono- and disaccharides, fibre (grams, gram/100 kcal) and salt (grams, gram/100kcal) per meal, day, week and study period

Dutch Healthy Diet index 2015 (DHD15-index) consists of fifteen components each representing one of the fifteen food-based Dutch dietary guidelines (2015). Per component the score ranges from 0 to 10, resulting in a final total range score between 0 (no adherence) and 150 (complete adherence).

Summary of questions on participants' perceived level of hunger, fullness, thirst and the desire to eat indicated on 100mm Visual Analogue Scales ranging from "Not at all" (0mm) to "Extremely" (100mm).

Waist to hip ratio circumference will be calculated by dividing the waist measurement (cm) by the hip measurement (cm).

Changes in water retention (kg, %) will be measured using bio impedance analysis (BIA)

24-hour glucose levels will be measured every 15 minutes using Continues Glucose Monitoring (CGM).

Blood HbA1c

VO2 and VCO2 measures will be measured using the ventilated hood for 30 minutes

Standardized method to determine oral processing behaviour as a personal trait (Carrot test).

The Dutch Eating Behavior Questionnaire (DEBQ) consists out of 33 questions which can be scored from "Never" (1) to "Very often" (5) and will be used to classify participants based on their eating behavior trait (restrained eater, emotional eater, external eater). High restrained eaters will be identified with DEBQ restrained eater scale ≥ 2.90 for males and ≥ 3.40 for females.

The Adult Eating Behaviour Questionnaire (AEBQ) will be used to characterize the appetitive traits of the participants. The questionnaire consists out of 35 statements which can be scored from "Strongly agree" (1) to "Strongly disagree" (5). The statements are summarized into the scales 'Enjoyment of food', 'Emotional over-eating', 'emotional under-eating', 'Food fussiness', 'Food responsiveness', 'Hunger', 'Slowness in eating', and 'Satiety responsiveness'.

The Reasons Individuals Stop Eating Questionnaire (RISE-Q15) consists out of 15 questions in which the reasons or eating cessation can be assessed. All items are scored on a 7-point frequency scale (Never, Rarely, Seldom, Sometimes, Often, Usually, and Always) and summarized into 5 subscales: decreased food appeal, physical satisfaction, planned amount, self-consciousness, and decreased priority of eating.

The conscious level of interception with its multiple dimensions potentially accessible to self-report will be accessed with the Multidimensional Assessment of Interoceptive Awareness version 2 (MAIA-2). MAIA-2 is a validated 8-scale state-trait questionnaire with 37 statements. The statements are scored from "Never" (0) to "Always" (5). The scales are 'Noticing', 'Not-Distracting', 'Not-Worrying', 'Attention regulation', 'Emotional Awareness', 'Self-Regulation', 'Body Listening', and 'Trusting'.

The satisfaction of the participants with the diets (baseline, UPF fast and UPF slow) will be assessed with the Diet Satisfaction Questionnaire (Dsat-28) [40]. The Dsat-28 is a validated questionnaire that consists out of five scales accessed by 28 statements about the characteristics of the lifestyle and attitudes of individuals that reflect satisfaction within the diets. The agreement to the statements will be scored from "Disagree strongly" (1) to "Agree strongly" (5). The scales are 'Healthy Lifestyle', 'Eating Out', 'Costs', 'Preoccupation with Food', and 'Planning and preparation' . Only questions that are applicable will be asked (e.g. for the test diets no questions belonging to the scales Costs or Eating Out will be asked).

Using the Food Frequency Questionnaire (FFQ) the dietary intake at baseline will be measured in terms of macro(nutrients) and NOVA class.

Alpha-amylase activity and stimulated saliva flow rate

measured in mm/hg after an overnight fast

Physical activity will be measured using accelerometry

Physical activity will be measured using exercise diaries

The International Physical Activity Questionnaire-Short Form (IPAQ-SF) records the activity of the last 7 days on four intensity levels: 1) vigorous-intensity activity such as aerobics, 2) moderate-intensity activity such as leisure cycling, 3) walking, and 4) sitting. It estimates energy expenditure based on reported physical activity.

Inflammatory and leaky gut markers will be measured by measuring changes in C-reactive protein (CRP), IL-6, IL-8, TNF-α,levels of zonulin, gamma-glutamyltransferase, leukocytes, lipopolysaccharide-binding protein, soluble CD14, bactericidal increasing protein, peptidoglycan in fasted state.

The bolus properties the mixed meal tolerance test will be analysed on total number, surface area (mm2), and particle size (mm2 or mm).

The bolus properties the mixed meal tolerance test will be analysed on the amount of saliva uptake (g).

Measuring of fecal metabolite profile (SCFAs, tryptophan metabolites and bile acids), metagenomics, microbiota composition, and water content of fecal samples

Measure of gut transit time using the blue dye test

The Irritable bowel syndrome severity scoring system (IBS-SSS) will be used to assess the severity of IBS (gastrointestinal symptoms). The IBS-SSS consists of five questions in which severity of IBS symptoms in the last 10 days will be assessed on a 0 - 100 VAS scale. The sum of the scores of these five questions indicate the severity of IBS with a maximum achievable score of 500. Scores of 75 - 175 indicate a mild form of the disease, 175-300 a moderate form and scores of 175-300 indicate a severe type of IBS.

Participants will be asked classify their stool on the Bristol Stool Form Scale (BSFS). The BSFS is a 7-pont scale. The BSFS is an ordinal scale of stool types ranging from the hardest (Type 1) to the softest (Type 7). Types 1 and 2 are considered to be abnormally hard stools while Types 6 and 7 are considered abnormally loose/liquid stools. Type 3, 4 and 5 are therefore generally considered to be the most 'normal' stool form and are the modal stool forms in cross-sectional surveys of healthy adults.