The Acute Effects of Caloric Restriction on Anthropometrics, Metabolism, and Cardiovascular Health in Overweight Adults
Condition: Obesity; Overweight; Intermittent Fasting
MeSH terms: Overweight
Study type: Interventional

Summary: 
      The purpose of this study is to document the efficacy of a 3 day intermittent fasting/caloric
      restriction (IF/CR) using the Plexus® 3 day reset program on body weight as well as
      regulatory parameters of metabolism and metabolic flexibility. This study will provide data
      on the acute efficacy regarding the program but also identify the potential underlying
      physiological mechanisms through which the dietary intervention may elicit improvements, and
      the participant experience of the program. Collectively, this will provide a window into the
      possible adaptations with a longer-term dietary intervention.
    

Detailed description: 
      According to the US Centers for Disease Control, more than 42% of adults are classified as
      obese, and approximately 74% of US adults are classified as overweight (body mass index of
      25.0 to < 30 kg/m2) or obese (>30 kg/m2) (Ow/Ob). The costs on human health are profound,
      increasing the risk of heart disease, stroke, type 2 diabetes, and certain cancers, and
      ultimately increasing morbidity associated with these chronic diseases. Obesity and the
      negative sequelae inflict staggering economic costs, estimated at $147 billion, and that was
      in 2008. Therefore, understanding and developing interventions that can help address Ow/Ob
      can reduce the risk of chronic disease, reduce healthcare costs, and likely improve quality
      of life.

      One such intervention has been through altering diet and/or physical activity. However, prior
      systematic review and meta-analysis suggests that when comparing diet alone vs. exercise
      alone, dietary interventions result in ~3-fold greater weight loss (11 vs 3 Δkg). While the
      additional benefits of exercise are not be discounted, engaging dietary approaches can be a
      highly effective way to promote weight loss. Caloric restriction (CR) has long been touted as
      an effective method of inducing weight loss, although there are also issues with adherence
      and maintenance with such an approach. This study is seeking to understand the acute
      metabolic changes with engaging in a 3-day caloric restriction, which would typically be part
      of an intermittent fasting dietary regimen.

      Specific Aim 1. Document the efficacy of the 3 day IF/CR on inducing short term weight loss,
      the nature of the weight loss changes (body composition), changes in anthropometrics (waist
      and hip circumference), changes in resting metabolic rate and changes in metabolic
      flexibility (relative utilization of fats versus carbohydrates).

      Specific Aim 2. Explore the physiological responses to the 3 day IF/CR with the Plexus 3 day
      reset program through analysis of blood plasma for levels of insulin, glucose, lipid profile
      (total cholesterol, high- and low-density cholesterol (HDL/LDL)), pro- and anti-inflammatory
      mediators (Tumor Necrosis Factor-alpha, TNFa and Cortisol, respectively), ketones, thyroid
      stimulating hormone (TSH), and hormones related to hunger and satiety and thus energy intake
      (protein YY (PYY), neuropeptide Y (NPY), Ghrelin, and Leptin).

      Specific Aim 3. Ascertain any possible changes in clinically relevant parameters such as
      heart rate, heart rate variability (HRV), blood pressure (central and peripheral), and
      vascular stiffness (augmentation index, AIx).

      Hypothesis: The investigators hypothesize that the nutritional intervention will induce
      weight loss, changes in anthropometrics/body composition (i.e. decreased body water), resting
      metabolic rate, and alterations in metabolic flexibility. These measures will be explained,
      at least, in part, by alterations in specific blood biomarkers. The investigators also
      hypothesize that the 3 day IF/CR will result in improved indicators of cardiovascular health.
    

Intervention name(s): 3 day caloric restriction/metabolic reset
Intervention type(s): Dietary Supplement
Intervention description(s): Participants will consume ~500 kcal/day, using commercially available products (Plexus(r)), for 3 days, measuring physiological relevant parameters pre-and post-intervention.
Intervention model: Single Group Assignment
Intervention model description: This study will utilize a pre-post interventional design to assess the acute effects of a 3 day caloric restriction protocol.
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: intermittent fasting; caloric restriction