Obesity clinical trials at UC Davis
10 research studies open to eligible people
open to eligible people ages 20-45
The purpose of this research is to investigate whether consuming two different kinds of olive oil will change risk factors related to cardiovascular disease, including levels of good and bad cholesterol, levels of inflammation, and levels of gene expression.
open to eligible females ages 18-45
This study is designed to compare two types of snacks (almonds or a cereal-based snack), eaten between meals, on measures of appetite, including appetitive hormones, self-reported feelings of hunger and fullness, and food intake at a buffet meal or in the home environment. The investigators hypothesize that the acute responses of appetitive hormones to a meal challenge protocol will differ between almond and cereal-based snacks based on multivariate models of satiety that will be predictive of ad libitum food intake at a dinner meal as part of the meal challenge protocol. Further, the investigators will estimate if, under free-living conditions, self-selected and self-reported food intake will show appropriate energy compensation for the added calories of the snacks, and determine if one type of snack is superior to the other in this regard.
A Study of the Effects of Sweet Cherry Juice on Metabolism (converting food to energy) and Heart Health
open to eligible people ages 20-65
This study aims to determine the effects of consuming sweet cherry juice on cardiovascular function, glucose regulation, and lipid status in overweight human subjects. The investigators hypothesize that sweet cherry juice consumption will improve metabolic and physiological status in overweight persons compared to a placebo.
open to eligible people ages 21-70
Time-restricted eating (TRE) is a dietary manipulation that involves restricting food intake to 6-12 h/day with no energy intake the rest of the day. In rodents, TRE improves metabolic function without caloric restriction, potentially by activating nutrient sensing mechanisms and effects on circadian oscillations. However, an understanding of the effect of TRE on cardiometabolic health in people is not clear and few studies have evaluated this issue. Accordingly, the investigators propose to conduct a randomized controlled trial in people with obesity and prediabetes to determine the effect of 9 h TRE for 12 weeks, without a change in body weight, on key metabolic outcomes that are risk factors for cardiovascular disease (CVD): 1) multi-organ insulin sensitivity; 2) 24 h metabolic homeostasis and diurnal rhythm; and 3) adipose tissue and skeletal muscle biology. The proposed studies will elucidate the cardiometabolic implications of TRE in people with obesity and prediabetes.
open to eligible people ages 25-75
Numerous studies have established the role of nutrition on obesity and its related metabolic diseases, which together affect a billion individuals worldwide. Evidence indicate that meal timing regulates numerous metabolic processes suggesting that meal time manipulation may be a simple intervention against obesity and its metabolic diseases. Time-restricted eating (TRE) is a dietary manipulation that involves restricting food intake to 6-10 h/day with no energy intake the rest of the day. In rodents, TRE significantly decreases hepatic steatosis and dyslipidemia, while it supports a healthier hepatic cellular content even without caloric restriction, potentially by alternating activation of nutrient sensing mechanisms and effects on circadian oscillations. However, an understanding of the effect of TRE on liver health in people is not clear. Accordingly, we will conduct a randomized controlled trial in people with overweight/obesity and hepatic steatosis to determine the effect of 9 h TRE for 12 weeks, on key metabolic outcomes in liver health: 1) intrahepatic triglyceride content using magnetic resonance imaging; 2) de novo lipogenesis during fasting and postprandial conditions using administration of deuterated water in conjunction with mathematical modeling. The proposed study will enable us to determine the effect of meal timing on metabolic function in people with NAFLD.
“We're looking for healthy pregnant people to participate in a mobile health program”
open to eligible females ages 18-44
Despite the negative consequences to maternal-child health from women gaining too much weight during pregnancy, up to 62% of overweight and obese women gain more pregnancy weight than is recommended. This project will establish the efficacy of Goals for Reaching Optimal Wellness (GROWell), an mHealth tool for achieving appropriate pregnancy weight gain and promoting postpartum weight loss among women who enter pregnancy overweight or obese. GROWell will fill a gap in research and clinical care by providing a validated, standalone mHealth tool for weight control during pregnancy and postpartum, which is a currently lacking resource.
“We are inviting women to participate in a research study to test the health benefits of honey-flavored yogurt!”
open to eligible females ages 45-65
A randomized, double-blind, crossover dietary intervention trial will test the effects of 4 weeks of daily honey-flavored yogurt intake on markers of inflammation (Th17 cytokines) and oxidative stress (NOX2, UA, RSNO) and associative changes with microbial derived metabolites (SCFAs, BAs, ellagitannins), metabolism and the fecal microbiome. The above suite of selected markers will capture diet-induced systemic changes in inflammation and oxidative stress, while assessing associated microbial changes.
Metabolic and Bio-Behavioral Effects of Following Recommendations in the Dietary Guidelines for Americans (DGA4ME) Study
open to eligible females ages 35-64
This study, at the Western Human Nutrition Research Center (WHNRC), will focus on whether or not achieving and maintaining a healthy body weight is the most important health promoting recommendation of the Dietary Guidelines for Americans (DGA).The investigators hypothesize that improvement in cardiometabolic risk factors resulting from eating a DGA style diet will be greater in people whose energy intake is restricted to result in weight loss compared to those who maintain their weight. The investigators further propose that during a state of energy restriction, a higher nutrient quality diet such as the DGA style diet pattern, will result in greater improvement in cardiometabolic risk factors compared to a typical American diet (TAD) pattern that tends to be lower nutrient quality (more energy-dense and less nutrient-rich.)
“Using tissue samples to better understand the metabolism and genetics of obesity”
open to eligible people ages 18-55
Research the genetic and biomechanical markers of human adipose tissue on patients with morbid obesity. Additional tissue/fluid collection is also gathered during the time of surgery.
“Postmenopausal Women Needed for a Research Study”
open to eligible females ages 45-65
This study seeks to confirm and extend previous finding that four weeks of daily intake of 40 g of walnuts improve microvascular function, increasing the reactive hyperemia index (RHI), effects which were greatest in individuals with the worst initial RHI and correlating to circulating levels of vasoactive plasma epoxides. The current trial will enroll postmenopausal women who are at risk for cardiovascular disease due to their menopausal status and increased central adiposity. The initial trial focused on non-esterified (i.e. plasma) derived oxylipins, but substantial and unique changes were also observed in the esterified lipoprotein pool. The current study will add the esterified lipoprotein pool, important, as the mechanisms by which walnut intake influences endothelial function are currently undefined, but may include lipoprotein induced modulation of vascular hemostasis. As a secondary objective, primary metabolism and urolithin metabotype will be analyzed as a way to capture the influence of potential differences in habitual diet and metabolism on physiologic response. Therefore, this study will combine measures of cardiovascular physiology, metabolomics, and walnut-derived metabolite analyses to assess the 12 week influence of 40 g of daily walnut intake on the health of overweight and obese postmenopausal women.