The Munchie Lunch Study: The effects of consuming different types of lunch on satiety in healthy males

This study will be conducted using a randomised, crossover design. All participants will be asked to attend a screening session (in order to determine their eligibility) and five test sessions with lunches varying in energy content. During the screening visit, participants will be asked to give informed consent, to complete several questionnaires, and some basic anthropometric measurements such as height, weight, body composition, waist and hip circumferences will be taken. Following this, participants will be asked to attend five test sessions, with a minimum of seven-day washout period between the test sessions. Participants will be asked to consume a pre-package study breakfast (around 500 kcal) in the morning on the test day. The same study breakfast will be provided on all five test days and participants will be asked to finish the entire study breakfast. During each test session, participants will be randomly allocated to receive one of the five test lunches, e.g. 150 kcal, 300 kcal, 600 kcal, 900 kcal or 1200 kcal of noodle soup. Noodle soup has been chosen as the test lunch as it is a popular and typical lunch in Asia. All test lunches contain the same ingredients, e.g. noodle, miso dashi broth, sesame seeds, chicken, zucchini, spring onion, mung bean, sea weed, fish cake, sesame oil, and canola oil, albeit the proportion of each ingredient differs between test lunches. Thus the amount of macronutrient and energy density vary across treatments, ranging from 18-26 g for protein, 4-63 g for fat, 14-136 g for carbohydrate, 0.27-1.81 kcal/g for energy density. The test lunches are matched for palatability, sensory properties, and weight. They will be covertly manipulated and hence participants will be blinded to the treatments they receive. Participants will be asked to consume the entire portion of the test lunch served. They will also be asked to rate their appetite every fifteen minutes for the first hour and every 30 minutes thereafter until they return for their evening meal. Participants are allowed to leave the study site after lunch and they will be asked to return for their evening meal 5 to 5.5 hours after lunch. They will be given a pre-package afternoon snacks before they leave the study site and they are allowed to have the afternoon snacks if they are hungry before the evening meal (optional). Participants are allowed to consume as little or as much food as they wish till they are comfortably full (i.e. ad libitum intake) for the evening meal. On each test day, participants are allowed to consume one black coffee or tea without sugar. All participants will be asked to complete a one-day food diary on the test day in order to monitor their adherence to the study protocol. In addition, all participants will be asked to complete some sensory measures during the study. Participants will also be encouraged to continue their habitual diet and physical activity during the intervention.