Clinical Research Directory

Validation of a Novel Cerebellar-striatal Satiety Circuit in Humans

This study uses a noninvasive technique called transcranial magnetic stimulation (TMS) to study satiety in healthy individuals. TMS is a noninvasive way of stimulating the brain, using a magnetic field to change activity in the brain. The magnetic field is produced by a coil that is held next to the scalp. In this study, the investigators will be stimulating the brain to learn more about the role of the cerebellum in satiety.

Exercise, Brain Activity, and Weight Maintenance

This study aims to explore how HIIT influences brain function, neural and molecular pathways related to weight control, setting the stage for future obesity intervention research.

Food for Thought: Executive Functioning Around Eating Among Children

Scientific knowledge of the cognitive-developmental processes that serve to support children's appetite self-regulation are surprisingly limited. This investigation will provide new scientific directions for obesity prevention by elucidating cognitive-developmental influences on young children's ability to make healthy food choices and eat in moderation.

Timing and Resistance Exercise: Impact on Eating and Metabolism

Exercise timing (morning or evening) for optimal weight control is a research topic urgently addressed by scholars in the relevant field. Due to the better control of energy metabolism and physical activity levels in the morning, existing research on resistance exercise and eating behavior primarily focuses on experiments conducted in the morning, with only one study in the afternoon. No research has yet compared the potential differences between morning and evening resistance exercise. A one-year study aims to investigate the impact of morning and evening resistance exercise on physiological metabolism and eating behavior. Eighteen healthy male participants will be randomly assigned to a crossover design study, including AM exercise, PM exercise, and control (rest condition) trials. Variables including subjective appetite, appetite hormones (ghrelin, peptide YY), food preferences, ad libitum eating, dietary records, energy expenditure, and PBMCs circadian rhythm genes will be measured. This preliminary study through a multidimensional observation, the results will contribute to understanding the potential differences and mechanisms of morning and evening resistance exercise on physiological metabolism and eating behavior. In practical applications, conducting resistance exercise in the evening or at night aligns better with current lifestyles. The findings of this study can support the optimization of exercise benefits by validating the choice of exercise timing.

Investigating the Glycaemic and Satiating Capacity of PulseOn® Enriched Foods

The purpose of this randomised control trial is to determine whether consuming PulseOn enriched crackers for breakfast influences post-prandial glycaemic response and markers of appetite (hunger, fullness, desire to eat) over 4 hours, and energy intake at an ad libitum lunch meal on the same day. Healthy individuals with no underlying metabolic disease will be recruited to take part in this study.

Gut Hormone LEAP2 in Metabolism and Eating Behaviour: Fixed Meal Testing

The goal of this interventional study is to measure the blood levels of the gut hormones LEAP2 and acyl ghrelin (AG), appetite and food intake after consuming liquid meals of different caloric sizes, in healthy adults with and without obesity. AG is a stomach-derived homone that increases appetite, and LEAP2 a liver-gut derived hormone that decreases appetite, which interferes the action of AG ant its receptor in the brain called the growth hormone secretagogue receptor (GHSR). Blood levels of AG and LEAP2 change in opposite directions after food intake (AG decreasing, LEAP2 increasing). AG is formed from an inactive version of hormone called desacyl ghrelin (DAG). Previous studies have shown that greater food intake leads to a greater decrease in blood levels of total ghrelin (AG + DAG), but this has not been studied for changes in blood AG or LEAP2 after eating. Blood levels of AG and total ghrelin when fasted and after food intake are lower, while blood levels of LEAP2 are higher, in adults with than those without obesity. The main study questions are: 1. Are there greater increases in blood levels of LEAP2 and greater decreases in blood levels of AG after consuming larger meals (by amount of calories they contain)? 2. Are greater decreases in appetite after connsuming larger meals related to greater increases in blood levels of LEAP2 and greater decreases in blood levels of AG? 3. Are greater decreases in food intake at a buffet lunch after consuming larger meals eaten a few hours previously related to greater increases in blood levels of LEAP2 and greater decreases in blood levels of AG? 4. Do the above findings differ between adults without obesity and with obesity? At each of 4 study days, healthy adults (without and with obesity) will consume one size of a single liquid meal containing different amounts of calories (0, 600, 900 (group without obesity only), 1200, 1800 (group with obesity only) kilocalories, of identical total volume) after an overnight fast and have measurements of blood LEAP2 and AG and appetite ratings from 0 to 180 min, and have food intake at an ad libitum lunch measured at 180 mins. Food will be weighed and converted into kilocalories. All participants will attend for all 4 study visits in a randomised order to receive one of the meal sizes at each visit, so that all 4 meal zizes are consumed over all 4 study visits: 0, 600, 900 (group without obesity), 1200, 1800 (group with obesity) kcal.

Exogenous Ketones and Appetite

People with obesity have different appetitive responses to stimuli compared to people without obesity. For example, people with obesity have a blunted postprandial ghrelin ('hunger' hormone) response, lower glucagon-like peptide 1 (GLP-1) and peptide-YY (PYY; associated with satiety) compared to people without obesity. Given the favorable effects of exogenous ketones on appetite previously observed in healthy adults of normal body weight, it is possible that these supplements can alter appetite hormones in a manner that may closer match that observed in people without obesity. To explore this research question, investigators will conduct a randomized single-blind cross over study to characterize appetite and dietary intake after ingestion of an exogenous ketone supplement within adults with obesity (compared a control condition without exogenous ketones) and compared to adults without obesity. The research team will also explore differences in postprandial energy expenditure and fuel utilization. Twenty-two healthy young- and middle-aged adults will be included (up to n=26 enrolled). In addition to a baseline visit to measure body composition, participants will undergo two 4.5-hour study visits, one of which will include a ketone diol supplement and one will have a placebo. Participants will be given a 1-day run-in diet prior to each study day to support energy balance. On each study day visit, participants will undergo a resting metabolic rate test (indirect calorimetry) followed by a fasting appetite rating and blood sample collection. Participants will then be provided with a standard breakfast meal (one with the ketone supplement and one with placebo). Appetite ratings and blood sample collection will be repeated 60, 120, and 180 minutes after the meal. Indirect calorimetry will be completed after the 30, 90, and 150 minute assessments. After the 180-minute timepoint, participants will be provided with a buffet-like lunch meal with instructions to eat as much or as little as they would like to determine ad libitum dietary intake at a single meal. To assess free-living ad libitum dietary intake, participants will receive 1.5 days of food boxes tailored to their preferences, with uneaten food returned at the end of the 1.5-day period. This study will be the first to assess the impact of exogenous ketones on appetite in obesity and would help inform future weight loss intervention trials.

Effect of Oral Lactate Ingestion on Appetite Regulation

The goal if this study is to determine how oral lactate ingestion affects markers of appetite regulation. Researchers will compare oral lactate ingestion to a sodium chloride placebo. Participants will consume the lactate or placebo solution and then have blood samples and assessments of appetite over the course of 90 min. Free-living energy intake will be measured for 3 days surrounding each experimental session.

Appetite and Dietary Intake Across the Menstrual Cycle

Lay language summary: Women are younger and menstruating about monthly ("pre-menopausal") often have fluctuations in the food they eat ("dietary intake") across the menstrual cycle. However, relationships between food intake and appetite, metabolism, body composition (i.e., the proportion of muscle and fat), physical activity and premenstrual symptoms have not been reported. This study will measure appetite and food intake in laboratory and usual life settings in healthy pre-menopausal women in two hormonally different parts of the menstrual cycle. Data on ovarian hormones, metabolism, body composition, physical activity and premenstrual symptoms will also be collected to assess their potential relationship with food intake.