RecruitingNot ApplicableNCT06309576

Experimental Approach to Test Predictions of Body Weight Regulation Models

Sponsor

Pennington Biomedical Research Center

Enrollment

12 participants

Start Date

Jan 17, 2025

Study Type

INTERVENTIONAL

Conditions

Obesity Underweight

Summary

The regulation of human body weight and fatness is not fully understood. Although some models of regulation have been proposed (set point, dual-intervention point, others), no studies have been designed to test their predictions. In this pilot and feasibility study, the investigators will implement an experimental approach to test the predictions of models of body weight regulation in humans. Men and women with either low body weight or obesity will be exposed to a 2-day fasting followed by a 2-day ad-libitum refeeding. During the entire fasting-refeeding period, energy intake and expenditure will be accurately measured within metabolic chambers. The investigators will therefore determine the compensatory responses to fasting elicited to prevent weight loss. The results will serve to design and power future studies to better understand body weight regulation.

Eligibility

Min Age: 18 YearsMax Age: 40 Years

Inclusion Criteria7

Body mass index lower than 20 kg/m2 for the low body weight group, or 30 kg/m2 or greater for the obesity group
-40 years old
Nulliparous and regular menstrual cycle (25-35 days) during the last six months (in women)
Normal thyroid function, blood count, and chemistry 15 panel (normal plasma glucose will be considered at <100 mg/dL; normal serum HDL cholesterol at >=50 mg/dL for women and >=40 mg/dL for men; and normal serum triglycerides at <150 mg/dL).
Self-reported weight stability during the last six months (±3 kg)
Rate the liking of at least one of the flavored liquid meals (Ensure Plus, Abbot Nutrition) between 5 and 8 on a 9-point Likert scale
Willing to only drink up to two assigned flavors of Ensure Plus for two consecutive days

Exclusion Criteria14

Eating disorders as indicated by a global score ≥2.80 in the Eating Disorder Examination Questionnaire, or a previous diagnosis of an eating disorder
For the low body weight group, having food insecurity (with or without hunger) as assessed by the USDA
Recreational moderate-intensity physical activity ≥150 min/week, recreational vigorous-intensity physical activity ≥75 min/week, or a combination of recreational moderate-intensity and vigorous-intensity physical activity (moderate time + \[2 × vigorous time\]) ≥150 min/week as assessed by the Global Physical Activity Questionnaire, or being a professional athlete
Cigarette or vape smoking
Intake of more than 14 alcoholic drinks per week
Use of medications that may affect energy intake and/or expenditure, for example, semaglutide, liraglutide, exenatide, other GLP-1 receptor agonists, phentermine-topiramate, naltrexone-bupropion, orlistat, metformin, SGLT2 inhibitors, pramlintide, levocarnitine, amphetamines, and amphetamine-like drugs
Human immunodeficiency virus, galactosemia, and lactose intolerance
Diseases that affect energy homeostasis including endocrine such as hypo/hyperthyroidism, or type 1 or 2 diabetes; cancer; chronic pulmonary diseases; cardiovascular disease; and renal disease
History of inflammatory bowel disease (ulcerative colitis, Crohn's), malabsorption syndromes (intestinal, pancreatic), and sprue or gluten intolerance
Having moderate to severe sleep apnea defined as an oxygen desaturation index \>10 times/hour assessed by overnight oximetry to be conducted on the night following the screening visit
Use of oral hormonal contraceptives or less than 6 months using a hormonal intrauterine device (in women)
Adults who are unable to consent
Prisoners
Currently pregnant or breastfeeding (in women)

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Interventions

BEHAVIORALFasting-refeeding cycle

Participants will be maintained in metabolic chambers and exposed to 1 day of energy balance with a standard diet, 2 days of fasting (only water), and 2 days of ad-libitum refeeding using a liquid diet provided in hydration bladders to avoid portion control.