Dr Macklin E. Guzman

Our research proves that Medi-Weightloss® patients lose weight and can improve their health!

In our largest and most comprehensive study, we found that our patients:  

  • Lost significant weight - body weight reduced by 14% in the first 13 weeks of the program and by 21% by week 39.
  • Reduced BMI - BMI dropped by five points in the first 13 weeks of the program and by almost eight points by week 52.
  • Lost body fat - body fat percentage decreased by about 12% in the first 13 weeks of the program.
  • Lost inches - waist circumference decreased by about 5 inches after 13 weeks in the program.
  • Improved cholesterol - HDL "good" cholesterol levels increased by 35% in 9 months and LDL "bad" levels decreased.
  • Lowered blood sugar - at week 13 serum glucose was found to have reduced by about 4%, and again by about 8% at 26 weeks.
  • Lowered blood pressure - Systolic Blood Pressure fell from an average of 125 mm Hg to an average of 118 mm Hg by week 13. Diastolic blood pressure fell from an average of 80 mm Hg to 77 mm Hg.
  • Eliminated or reduced their risk of developing Metabolic Syndrome - the prevalence of MetS within the study population was reduced by 45% in only 13 weeks and subsequently by 73% at 52 weeks in patients.

Click here to read: Effect of an intensive lifestyle intervention on the prevalence of metabolic syndrome and its compoents among overweight and obese adults.

Medi-Weightloss® prides itself on its evidence-based approach to treatment through clinical research.

Obesity and its associated comorbidities have become a public health problem of unprecedented proportions in this country and around the world. Medical professionals are in the unique position to properly address the needs of patients affected with excess weight and obesity. Almost a decade ago, the American Medical Association recognized obesity as a disease that requires a range of medical interventions.

Medi-Weightloss® offers a proven and individualized treatment and it prides itself on its evidence-based approach to treatment through clinical research and translational science. Translational science seeks to build on basic and clinical research in order to develop new therapies, enhance clinical guidelines, and assist with clinical decision-making.

As the industry leader in physician-supervised weight management, our clinical research is part of our commitment to making advances in weight management, allowing our healthcare professionals to implement these advances and bring them to our patients. As the science evolves, so do our programs and services. Thus, patients have come to expect not only weight loss success, but also quality medical care for their obesity.

Our scientists, physicians, and researchers attend and have been invited to present research and lead expert round-table discussions at several scientific and medical conferences, including The Obesity Society’s Obesity Week. Other conferences attended are affiliated with the following organizations:

  • Obesity Medicine Association Conferences
  • American College of Lifestyle Medicine Conferences
  • World Obesity Federation
  • Your Weight Matters (OAC)
  • The World Congress on Insulin Resistance, Diabetes, and Cardiovascular Disease

Our physicians and scientists are regularly interviewed and consulted as subject matter experts on obesity, preventive medicine, lifestyle medicine, and public health.

Our research was published in the peer-reviewed Journal of Public Health available through Oxford University Press.

The Scientific Advisory Board

In March 2012, Medi-Weightloss® held its inaugural meeting of the Scientific Advisory Board.

The board’s purpose is to critically review the effectiveness, safety, and added value of the Medi-Weightloss® treatment guidelines and products through outcomes research. This panel of physicians, scientists, and public health experts also assists in guiding the development of translational research studies that move scientific discoveries from university laboratories to the patient care setting.

The initiatives of this interdisciplinary team are shaped by the company’s dedication to quality assurance and the timely integration of clinical research findings into patient care. These efforts help assure that Medi-Weightloss® is and will always be The One that works!® – for patients, for physicians, and for investors.

Board Members

  • Edward A. Zbella, MD, CPI, FACOG, FACS, Chief Medical Officer, Medi-Weightloss® Corporate Headquarters, Tampa, FL, US
  • Macklin E. Guzman, DHSc, MPH, Vice President of Research and Development/Chief Compliance Officer, Medi-Weightloss® Corporate Headquarters, Tampa, FL, US
  • Jennifer L. Nguyen, PhD, MPH, CPH, Postdoctoral Associate, The Minority Cancer Research and Training (MiCaRT) Center, University of Florida, Orlando, FL, US
  • Eva Imperial, MD, Family Physician (specializing in women’s health), Vista Women’s Healthcare, Columbia, SC, US
  • Frank J. Troncale, MD, FACG, Medical Director & Physician, Medi-Weightloss®, Orange, CT, US; Affiliations include: Yale- New Haven Hospital/Saint Raphael Campus, Milford Hospital and Yale-New Haven Hospital.
  • Suzi Hancock, RNC-OB, WHNP-BC, Nurse Practitioner/Office Manager, Medi-Weightloss®, Waco, TX, US
  • Jamie King, APN, Nurse Practitioner, Medi-Weightloss®, Peoria, IL, US
  • Christina Holub, PhD, MPH, Research Associate, Institute of Behavioral and Community Health, San Diego State University, San Diego, CA, US
  • Elise Schram, MPH, CHES, Program Assistant for Special Projects, Illinois Public Health Institute, Chicago, IL, US

Patient Outcome

Metabolic Syndrome (MetS)

Do you suffer from MetS?

This study assesses the impact of a physican-supervised nonsurgical medical weight management program on the prevalence of MetS and it's key indicators. Download the article.

Dietary Supplements

Appetite Suppressant Medication vs. Herbal Supplement

Patients who are prescribed phentermine have been found to lose weight at a greater rate than patients who are prescribed phendimetrazine or an herbal appetite suppressant. Download the phentermine research.

Signature Shakes & Bars

Patients who purchase Signature Shakes & Bars have been found to lose more weight than patients that do not. Download Signature Shakes & Bars research.


Weight Loss and Weight Maintenance

Body Composition

Patients have been found to lose more body fat, as a percentage of lost weight, during the 4th through 12th weeks of the Medi-Weightloss® Program. Click here to download the research.

Patient Health Indicators

Changes in Type 2 Diabetes Risk

Many patients who are retested after having lost 25 - 35 lbs have been found to have lowered their risk of type 2 diabetes. Download diabetes research.


Many patients who attend the Medi-Weightloss® Program have been found to improve their blood pressure levels. Download blood pressure research.


Weight Loss Tools

Indirect Calorimetry

Patients who receive a BMR test with an indirect calorimeter at their Initial Consultation have been found to reduce their fat mass. Download BMR research.


Appetite Suppressant Medication

Patients who are prescribed appetite suppressants have been found to lose 45% more weight than patients who qualify for but decide not to take the medication. Click here to download the research.


Program Parameters

Weekly Injections

Patients who frequently receive a midweek injection have been found to lose more weight than patients who do not. Click here to download the research.

Program Adherence

Patients who visit their Medi-Weightloss® location approximately once per week have been found to lose a greater median percentage of their starting body weight than patients to don’t visit as often. Click here to download the research.

Social Support

Patients who enroll with a partner have been found to lose more weight. Click here to download the research.

Clinical Outcomes

Our Clinical Outcomes Brochure is available for download.


Our Weight Loss recipes

Try out our various weight loss recipes.


Signature Patient Website

Explore the various weight loss exercises available at our Signature Patient Website.


Medi-Weightloss® led a large five-year clinical trial called the Prospective Metabolic Indicator Study (PROMIS). This trial was the first of its kind anywhere in the world!

The main objective of PROMIS was to identify the prevalence of Metabolic Syndrome (MetS) in patients with obesity and more importantly, to assess the impact of weight loss on the disease process itself. This information allowed researchers to determine the effectiveness of the Medi-Weightloss® Program and its role in preventing the onset of MetS as well as other health conditions associated with obesity. In addition, to preventing MetS through weight loss, the study also evaluated the changes in key indicator. The study was also the first ever to report significant glycemic improvements (blood sugar) improvements after the early phase of a lifestyle intervention program.

  • 52% of Medi-Weightloss® patients screened positive for Metabolic Syndrome.
  • After participating in the program for 13 weeks, positive screenings decreased by 45%.
  • The prevalence of elevated glucose was also found to have improved significantly at week 13 from 56% to 44% and at week 39 from 54% to 24%.
metabolic syndrome analysis

This study reinforces prior research indicating that lifestyle choices and proper patient management are essential components of success in efforts to address the risk factors associated with metabolic syndrome and help patients effectively lose weight,” says Dr. Guzmán, additionally, the key here is the critical role that medical supervision plays in screening and treating metabolic syndrome, a disease that is typically under-diagnosed and under treated. Learning that one has metabolic syndrome can be a great motivator for adopting a healthier lifestyle. This study for the first time provides new clinical benchmarks indicating participation in the Medi-Weightloss® program can have a direct impact with improvements in many areas including waist size, cholesterol, triglyceride levels, and blood pressure.

Macklin Guzman, DHSc, MPH