This study will investigate how the acute intake of foods with high and low hedonic reward differentially affects brown adipose tissue and the interplay between gut peptides, brown fat, and the brain (gut-BAT-brain axis).
Background: The prevalence of obesity is alarmingly high and contributes to the dysfunction of other metabolic organs and tissues, increasing the risk of cardiometabolic diseases. Food products rich in sugar, sodium, and saturated fatty acids, i.e., with high hedonic reward, are shown to disrupt energy homeostasis by overriding the homeostatic control of food intake, promoting body weight gain. Contrary to white adipose tissue, brown adipose tissue uses glucose and triglycerides as fuel to dissipate energy as heat and has been considered an essential target for combating obesity. Recently, it has been shown that meal-induced thermogenesis (MIT) is associated with BAT function and that the postprandial secretion of secretin plays a role in BAT activation and satiety. Therefore, we hypothesize that foods with different degrees of hedonic reward (i.e high-palatable foods) affect the gut-BAT-brain axis, modulating energy homeostasis. Moreover, it differentially affects lean and obese individuals. Methods: This crossover clinical trial consists of two acute postprandial tests (low versus high-hedonic reward meals) with two weeks of washout. Thirty participants (15 lean and 15 with overweight/obesity) will undergo PET/CT scans with short-living radiotracers (\[15O\]-O2, \[15O\]-H2O PET/CT) before and after consumption of the two test meals to analyze BAT function. After food intake, one \[11C\]-carfentanil PET/CT will be carried out to understand the role of the brain in the gut-brain-BAT axis. Before and after the test meal, energy expenditure (indirect calorimetry) and circulating gut peptides will be analyzed to investigate the interplay between gut and BAT. The effect of organoleptic cues on the gut peptides and BAT will also be examined. Participants will answer dietary, behavioral, and physical activity questionnaires at the start of their participation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
30
Participants will consume a meal that corresponds to 40% of their daily resting metabolic rate and balanced diet but with low hedonic reward.
Participants will consume a meal that corresponds to 40% of their daily resting metabolic rate and balanced diet but with high-hedonic reward.
Turku PET Centre
Turku, Finland
RECRUITINGBrown adipose tissue metabolism
Brown adipose tissue metabolism will be assessed using 15O-O2 and 15O-H2O PET/CT, at room temperature, at fasting, after food cues, and after food intake.
Time frame: Fasting and postprandial (30 minutes after the consumption of two different meals, 2 weeks of washout between them)
Changes in gut peptides
Changes in gut peptides (secretin, GIP, GLP-1) from fasting to postprandial state (after intake of meals with high- or low-hedonic reward).
Time frame: Fasting and postprandial (30, 60, 90, and 120 minutes after meal intake)
Differences in μ-opioid receptors in the human brain
Differences in the brain's μ-opioid receptor (MOR) system (11C-carfentanil binding potential - BP). The differences between the two meals on 11C-carfentanil BP will be analyzed.
Time frame: The 11C-carfentanil binding potential (BP) will be analyzed 45 minutes after the consumption of the two meals (high or low-hedonic reward). The comparisons will be between the two meals.
Energy expenditure/Meal-induced thermogenesis
Changes in energy expenditure (from indirect calorimetry) after the intake of the two meals will be compared.
Time frame: Changes in energy expenditure after food intake (30 minutes, 1 hour 30 minutes and 2 hours 30 minutes after food intake)
Visual Analogue scale (VAS)
Changes in VAS after food intake compared to fasting
Time frame: Fasting, 30, 60, 90, and 120 minutes after food intake
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