When Simon Sum, DCN, RD, ACSM-CPT, ACSM-EIM, FAND, was a teenager, he struggled to gain weight. He was indulging in various cuisines, but nothing was working. Thus began his interest in nutrition. Now the director of scientific affairs of global product development at Herbalife, Sum loves his multifaceted role, which leverages his expertise as an RD, fosters continuous learning and positions him to drive business growth while advancing nutrition science and contributing to public health.

“By bridging science, industry and regulation, I’m proud to make a meaningful impact, prioritizing science-driven innovation and customer well-being,” he said.

From ensuring the safety and efficacy of Herbalife’s products to mentoring future dietitians through innovative programs like his sports nutrition partnership with LA Galaxy, Sum’s journey isn’t just about career success — it’s also about reshaping the way people approach wellness in a world full of misinformation.

Here’s the full interview.

Describe your role.

As director of scientific affairs at Herbalife, a premier health and wellness company, I lead efforts to ensure product safety, efficacy and scientifically backed claims through evidence-based practices. Beyond internal affairs, through key partnerships, I foster strategic external partnerships as a sustaining partner representative at the American Society for Nutrition and director-at-large of the California Academy of Nutrition and Dietetics Foundation. Furthermore, as a member of Herbalife’s Dietetic Advisory Board, I deliver global nutrition training and education to Herbalife distributors, driving nutrition expertise and excellence in nutrition guidance worldwide.

Why did you want to work in dietetics?

My passion for dietetics sparked during adolescence, when I struggled to gain weight despite my love for diverse cuisines. Determined to build muscle, I began weight training and delved into nutrition research. This journey revealed the pivotal role of informed eating in optimizing health and performance. Fascinated, I discovered the profession of registered dietitians — experts bridging food science, nutrition and wellness. This epiphany guided my decision to pursue nutrition in college, setting the stage for a fulfilling career as a credentialed nutrition expert.

How did you get the job at Herbalife?

During my clinical nutrition tenure in the hospital, I recognized a significant knowledge gap surrounding dietary supplementation among patients. With over 70% of U.S. adults using dietary supplements, I saw an opportunity and a need for RDs to provide expert guidance. However, I realized that our profession’s curriculum often overlooks this critical area. To bridge this gap, I sought hands-on experience in the industry, where innovation and cutting-edge research are extremely important. In 2012, I joined Herbalife’s science team, where I’ve had the privilege of staying abreast of the latest developments and contributing to evidence-based product development. I’m grateful for this enriching experience and thrilled to continue collaborating with our exceptional team.

What do you like about it?

With a passion for advancing nutrition science, I love this diverse role that encompasses various health areas, including weight management, digestive health, mental wellness, heart health, skin health and sports nutrition, etc. I’m responsible for reviewing research studies to inform product development, ensuring scientifically substantiated marketing materials and collaborating with trade and professional associations to shape industry guidelines. Additionally, I have the opportunity to navigate complex regulatory requirements for international product launches, staying up to date on country-specific regulations.

What has been the biggest challenge for you as a dietitian working in the industry?

Staying ahead of nutrition trends and combating social media misinformation poses a significant challenge. As RDs, it’s our responsibility to remain up-to-date and provide accurate guidance to the public. With the rapid spread of diet trends on social media, consumer inquiries can flood in quickly, demanding prompt and evidence-based responses. The alarming fact that only 2% of TikTok diet and nutrition trends are accurate highlights the critical role RDs play in separating fact from fiction.

What is one thing you wish you had known before starting your career in dietetics?

Reflecting on my journey, I wish I had earlier insight into the vast array of roles available in dietetics. Despite this, my diverse interests have led me to a fulfilling career. Beyond my full-time director of scientific affairs position, I’ve had the privilege of serving as a clinical dietitian, clinical nutrition manager, nutrition consultant, adjunct faculty, guest lecturer, preceptor and radio program host. Each experience has enriched my expertise, shaping me into a well-rounded RD.

Has there been anything specific that helped you move forward in your role?

The ever-evolving landscape of dietary ingredients and their health benefits is fascinating. Critically assessing research studies is vital to validate their safety and effectiveness. It’s rewarding when evidence-based science supports the health benefits, leading to innovative product launches to enhance public well-being. Beyond my own work, mentoring aspiring RDs and students and inspiring them to join the industry brings great joy. Together, we can create better and more effective nutrition solutions for the benefit of all.

Is there a program or initiative that you are most proud of?

I’m thrilled to have played a role in establishing the sports nutrition rotation for California-based dietetic interns from different dietetic internship programs, made possible through Herbalife’s partnership with LA Galaxy, a men’s professional soccer team. As sports nutrition continues to gain momentum, this program addresses a critical gap in training opportunities for future RDs. It’s truly inspiring to see our Herbalife RDs mentor interns alongside professional athletes, providing an unparalleled learning experience that will leave a lasting impact on their careers in sports nutrition.

Have any “hot topics” in the dietetics/nutrition industry impacted the way you do things?

The growing reliance on obesity medications underscores the need for holistic weight management strategies. As a registered dietitian and certified personal trainer, it is important to emphasize that lasting results require a balanced diet and regular physical activity. Medications can support, but not replace, lifestyle changes. By investing in nutritious eating and exercise habits, individuals can gain long-term benefits. I’m dedicated to educating the public and promoting sustainable wellness practices, ensuring that individuals have the tools for a healthy, vibrant life.

Bio: Simon Sum, DCN, RD, ACSM-CPT, ACSM-EIM, FAND is a clinical nutrition doctor and a registered dietitian nutritionist. He is currently the director of scientific affairs at Herbalife. His primary role is to ensure the safety and scientific integrity of Herbalife products and lead personalized nutrition initiatives. He is also a member of the Dietetic Advisory Board of Herbalife. In addition, Sum is a radio program host at AM1430, the Cantonese radio station in the greater Los Angeles area, where he provides a daily nutrition clip to the audience. Prior to joining Herbalife, Sum was the clinical nutrition manager at Alhambra Hospital Medical Center in California, where he managed clinical dietitians, dietetic technicians and interns and provided nutrition care to patients with various health issues. Sum is currently appointed as the director-at-large for the California Academy of Nutrition and Dietetics Foundation, and previously, he was an appointed member of the Interoperability and Standard Committee of the Academy of Nutrition and Dietetics in 2014-2017 and the elected chairman of the Chinese Americans in Dietetics and Nutrition in 2012-2013. Sum holds his doctorate degree in clinical nutrition from Rutgers University and two master’s degrees in medical research and nutritional sciences from The University of Hong Kong and California State University, Long Beach, respectively. He is also an American College of Sports Medicine’s certified personal trainer with exercise is medicine credential and a fellow of the Academy of Nutrition and Dietetics. Sum is a Hong Kong native who now calls Long Beach home, enjoying Southern California’s sunny charm.