Jonathan Pierce, MD

Jonathan Pierce MD
Jonathan Pierce MD

Leadership of Sierra Weight Loss is provided by Jonathan Pierce MD, practicing primary care medicine in the Grass Valley, Nevada City, and Roseville areas since completing his Internal Medicine residency at the UC Davis Medical Center in 1993. His abiding interest in aiding others to learn again to live in a normal weight body arises from a many-year personal struggle with his own obesity. In 2010 he participated in the Hernried Center's weight loss program, losing approximately 60 pounds over five months while conducting his busy medical practice. Not only has he kept off most of this for over two years but has marvelled at the good results a number of his patients have enjoyed who have subsequently employed this method. Their gratification at safely losing significant weight and enjoying very improved health is a real reward for their doctor!

Dr. Pierce completed medical school at Baylor College of Medicine, Houston, after over a decade of experience in social work and counseling, especially in Europe, where he had fairly extensive experience in various forms of alternative medicine. He is board certified in Internal Medicine and is especially dedicated to improving patients' chronic disease states.

Having thoroughly and personally tested this path to improved health, Dr. Pierce, along with Nurse Practitioner Mary Berg and Registered Dieticians Kelley Kull and Elizabeth Dreher, has resolved to help Sierra foothill residents in need of improved weight management. You are invited to join with them to open a new chapter of improved health and self-satisfaction in your own life.

Mary Berg, FNP

Mary Berg FNP
Mary Berg FNP

Mary Berg has been a Nationally Certified Family Nurse Practitioner since 2002. She has served in various capacities. First, as a Public Health Nurse and a provider for the Nevada County Teen Clinic in 2003. She currently provides care at Dr.Pierce's, Dr. Goddard's and Dr. Leon's. She is very supportive of patient's preventive care, and is looking forward to helping patients achieve their weight goals.

Kelley Kull, RD, CDE

Kelley Kull, RD, CDE
Kelley Kull, RD, CDE

Kelley brings over 20 years of experience as a Registered Dietitian and Certified Diabetes Educator to the Sierra Medical Weight Management team. After earning her bachelor’s degree in Dietetics and Nutrition from Chico State University and completing her dietetic internship and University of Virginia, Kelley has spent the majority of her career in the outpatient setting. Weight and disease management have been her focal point; working with countless patients and their families to establish crucial lifestyle changes. In her free time, she enjoys running marathons, hiking, skiing, and preparing new and healthy recipes for her family. She is excited about helping the Sierra Medical Weight Management patients reach their goals!

Elizabeth Dreher, RD, CDE

Elizabeth Dreher RD
Elizabeth Dreher RD

Elizabeth has a passion for healthy food, and enjoys her work as a Registered Dietitian. She obtained a bachelor’s degree in Nutrition and Food Science from CSU, Chico; then continued with her dietetic internship and graduate school in Portland, Oregon earning a master’s degree in Clinical Nutrition at Oregon Health & Science University. Elizabeth has experience in pediatrics, including diabetes counseling and education with children, teens, and families; and holds a certificate in childhood and adolescent weight management. She has also worked with geriatric populations, active duty serving our country, and as a clinical dietitian at our local hospital, Sierra Nevada Memorial. Elizabeth believes in a whole foods approach that cuts to the chase, allowing the body to heal and thrive by prioritizing nutrient density and ridding our diet of harmful foods. She is thrilled to be part of the SWL team.