A dietitian is a board-certified food and nutrition expert who may provide medical nutrition therapy and counseling. Some dietitians refer to themselves as nutritionists. But, nutritionist isn’t a regulated term in every state.

You may be wondering what defines true expertise in nutrition.

Perhaps you have heard the terms “nutritionist” and “dietitian” and are confused by what they mean.

This article reviews the differences between dietitians and nutritionists, what they do, and the education required.

It focusses on definitions and regulations in the United States and addresses international ones only to a small degree.

In the United States and many other countries, a dietitian is a board-certified food and nutrition expert. They are highly educated in the field of nutrition and dietetics — the science of food, nutrition, and their impact on human health.

Through extensive training, dietitians acquire the expertise to provide evidence-based medical nutrition therapy and nutritional counseling tailored to meet an individual’s needs.

They are qualified to practice across a span of settings, including hospitals, outpatient clinics, research institutions, or local communities, to name a few.

Degrees and credentials required

To earn the credentials of Registered Dietitian (RD) or Registered Dietitian Nutritionist (RDN), a person needs to complete the criteria set forth by governing bodies like the Academy of Nutrition and Dietetics (AND) in the United States or the Dietitians Association of Australia (1, 2).

Additionally, in some countries, people may earn the title of “registered nutritionist,” which is synonymous with “registered dietitian” and requires certification from a governing body.

These are professional organizations that oversee the field of dietetics in their respective countries.

To clarify, the credentials of RD and RDN are interchangeable. However, RDN is a more recent designation. Dietitians can choose which credential they would rather use.

To earn these credentials, dietitians-to-be must first earn a bachelor’s degree or equivalent credits from an accredited program at a university or college.

Typically, this requires an undergraduate science degree, including courses in biology, microbiology, organic and inorganic chemistry, biochemistry, anatomy, and physiology, as well as more specialized nutrition coursework.

As of January 1, 2024, all dietetics students must also hold a master’s degree to qualify for their RD board examination in the United States (3).

In addition to formal education, all dietetics students in the United States must apply for and be matched with a competitive internship program accredited by the Accreditation Council for Education in Nutrition and Dietetics (ACEND).

Similar internships may be required in other countries.

Internships typically expose the student to 900–1,200 unpaid supervised practice hours across the 4 domains of practice, with careful adherence to competencies, or specific areas of study, complemented by in-depth projects and case studies outside of those hours.

Furthermore, the student must usually pass an exit exam mirroring the content of the board exam before completing the internship. The successful completion of these requirements qualifies them to take a board examination.

Finally, a dietetics student who passes the board exam in their respective country can apply to become a registered dietitian.

Licensure

Earning dietitian credentials requires national board certification.

What’s more, 13 states, including Rhode Island, Alabama, and Nebraska, require that dietitians be licensed in order to practice. The remaining states either don’t regulate this profession or provide state certification or optional licensing (4).

The process of licensing sometimes has additional requirements, like passing a jurisprudence exam. This is meant to ensure that dietitians practice under a code of conduct to protect public safety.

The dietitian must also continue their professional development by completing continuing education credits, which helps them keep up with the ever-evolving field.

Types of dietitians

There are four main domains of practice for dietitians — clinical, food service management, community, and research.

Clinical dietitians are those who work in an inpatient hospital setting. Outpatient dietitians may also work in a hospital or clinic, but they work with people who aren’t admitted to inpatient care and are usually less ill.

Both inpatient and outpatient dietitians provide support to the medical team to treat many acute and chronic illnesses. Dietitians in long-term care facilities may also supervise the nutrition of people with serious conditions that require ongoing care.

They follow standards of practice and detail a person’s medical history and current status, including lab work and weight history. This allows them to assess acute needs, prioritizing life-threatening conditions.

Inpatient and outpatient dietitians also provide nutrition education to people with specialized needs, such as those newly out of surgery, in cancer treatment, or diagnosed with chronic illnesses like diabetes or kidney disease.

In the outpatient setting, they give more in-depth nutritional counseling working towards a nutrition-oriented goal.

Dietitians may also work in other settings like research hospitals, universities, or food service management.

They can advocate for public policies and provide expertise in the community setting, such as school districts or public health organizations like Women, Infants, and Children (WIC).

Food service management dietitians oversee the production of nutritionally adequate food that meets food safety guidelines within a large organization, such as a school district or military base.

A community dietitian can help design and implement programs aimed at populations instead of individuals, such as community cooking initiatives or diabetes prevention interventions. They can also advocate for public policies with a focus on nutrition, food, and health issues.

Research dietitians typically work in research hospitals, organizations, or universities. They operate within a research team headed by a primary investigator and carry out nutrition-focused interventions.

Once dietitians have earned their credentials and are working in the field, they can go on to specialize in a particular subcategory, such as pediatrics or sports dietetics.

Finally, dietitians may also run private practices to provide services like nutritional counseling.

They may additionally teach in an academic or research institution or write about nutrition-related topics. Others may work as health and nutrition experts in media or as public speakers.

Conditions dietitians treat

Dietitians are qualified to manage nutrition therapy across a span of acute and chronic conditions. The type of conditions they treat depends most on the setting of their practice.

This means that they can treat nutrition problems that may arise from cancer or its treatment, as well as work with a client to prevent the onset of diabetes.

In hospitals, they treat a range of people, such as those who are clinically malnourished, as well as those who require nutrients via feeding tubes.

Dietitians also treat people undergoing bariatric (weight loss) surgery or those with kidney issues, as these individuals can have many nutritional restrictions and benefit from individualized care to fully meet their bodies’ needs.

Eating disorder dietitians have usually acquired additional training or education to treat this population. They work with a team of psychotherapists and doctors to help individuals recover from these disorders (5).

Eating disorders include chronic starvation (anorexia nervosa) or binging and purging (bulimia) (5, 6).

Sports dietitians specialize in optimizing nutrition for enhanced performance in athletes. These dietitians may work in gyms or physical therapy clinics, as well as with a sports team or dance company (7).

Summary

Dietitians can apply their expertise across a broad range of settings, such as hospitals, research institutions, and sports teams. They may prescribe nutrition therapy to help treat or prevent acute and chronic illnesses.

In some countries, people may translate their title as “nutritionist” rather than “dietitian,” though their educational background closely resembles that of a dietitian.

In the United States, the title “nutritionist” may encompass individuals with a broad range of credentials and training in nutrition.

In over a dozen states, certain qualifications must be met before an individual can call themselves a nutritionist. Additionally, accredited certifications grant titles like Certified Nutrition Specialist (CNS) (8).

In most states, those who receive these certifications have the authority to practice medical nutrition therapy and other aspects of nutrition care.

In many states, such as Alaska, Florida, Illinois, Maryland, Massachusetts, and Pennsylvania, RDs and CNSs are granted the same state license, usually called a Licensed Dietitian Nutritionist (LDN) license.

In states that don’t regulate the use of this term, anyone with an interest in diet or nutrition may call themselves a nutritionist. These individuals may apply their interest in nutrition to anything from running a food blog to working with clients.

However, because uncredentialed nutritionists typically lack the expertise and training for medical nutrition therapy and nutrition counseling, following their advice could be considered harmful (9).

Before consulting a nutritionist, you may want to check whether your state regulates who may use this title.

Degrees and credentials required

In the U.S. states that don’t regulate the term, no degrees or credentials are required to be a nutritionist. You simply need an interest in the field.

In states that do mandate licensure, the CNS or RD credential may required.

Those with CNS credentials are health professionals like nurses or doctors with advanced health degrees who have sought out additional coursework, completed supervised practice hours, and passed an exam overseen by the Board for Certification of Nutrition Specialists.

Conditions that CNSs and other nutritionists treat

In the United States, CNSs have legal standing to treat health conditions in most states.

Over a dozen states also regulate the title “Licensed Nutritionist” or the more generic “nutritionist.”

CNSs or nutritionists with licensure may help treat any condition that an RD would.

Like RDs, CNSs prescribe nutrition therapy, which is specific care meant to manage or treat illnesses or other conditions. CNSs may also oversee community nutrition education programs.

Nonetheless, those without credentials or licensure may pursue approaches to nutrition that are outside the scope of traditional medicine. While some of these approaches may have robust scientific backing, others may not.

Giving nutrition advice without the proper knowledge and training can be harmful, especially when counseling those with health conditions.

As such, if you are considering consulting a nutritionist, you may want to ask if they are a CNS or have state licensure or certification, or another credential.

Summary

In the United States, the term “nutritionist” encompasses a broad range of credentials and expertise. Several states specifically regulate this term. Additionally, nutritionists may pursue an advanced CNS certification.

Dietitians and CNSs are credentialed, board-certified food and nutrition experts with extensive training and formal education.

Depending on where they live, dietitians and nutritionists like CNSs may also need to meet additional requirements to be licensed to practice.

Dietitians and CNSs can apply their expertise across a range of settings, including hospitals, academic institutions, and food service management. Some specialize in working with specific populations, such as children, athletes, or those with cancer or eating disorders.

Meanwhile, in the United States, the term “nutritionist” is regulated by certain states but not others. Thus, in many states, anyone can call themselves a nutritionist.

Though these titles can sometimes be easy to confuse, remember that professionals with the titles “RD” or “CNS” have advanced degrees in nutrition.

Acknowledgements

The editors at Healthline would like to thank Victoria Behm, MS, CNS, LDN, and Brittany McAllister, MPH, from the American Nutrition Association for contributing to this article and providing a final review.