A nutrition pro can help you optimize your fueling strategy and mitigate common running-related issues ranging from postworkout energy crashes to midrun bathroom trips. But knowing who to trust with your health is tricky. “Expert” is a relative term, and it turns out that the meaning of “nutritionist” varies depending on who you’re talking to.

So, how do you know who’s legit? For advice on finding a qualified practitioner (and knowing who to avoid), we spoke with three registered dietitians about the difference between a dietitian versus nutritionist. Here’s what you need to know.

Dietitian vs Nutritionist: What’s the Difference?

The difference between a nutritionist and a dietitian comes down to education, experience, and credentials. Registered dietitians (RD) are trained at the university level, and starting in 2024, they must have at least a graduate-level degree to be eligible to take the Commission on Dietetic Registration’s (CDR) exam to earn the RD designation. Prospective registered dietitians also participate in an internship where they accrue between 900 and 1,200 hours of supervised practice.

A certified nutrition specialist (CNS) has similar training to a registered dietitian but is accredited through the American Nutrition Association (ANA), which requires that test takers have a master of science or doctoral degree in nutrition or a related field. Like registered dietitians, they must also complete around 1,000 hours of supervised practice.

Both registered dietitians and certified nutrition specialists are required to obtain separate licenses in the states where they practice and regularly earn continuing education credits to keep their accreditations.

The requirements or qualifications for a “nutritionist” or “nutrition coach” are far less rigorous. In fact, there are none.

“Anyone can call themselves a nutritionist,” says Marie Spano, MS, RD, CSCS, CSSD, sports dietitian. “There’s no regulation behind that term.”

Some nutritionists earn certificates through universities or private companies, but coursework varies from one institution to the next, and there are no universal standards for program evaluation or testing. Some nutritionists forgo formal education altogether, relying on their own research or personal experience to inform their work.

If you have any nutrition-related illnesses, a nutritionist who’s not an RD or CNS technically is not allowed to treat you—that includes meal planning, diet recommendations, or supplementation. “Let’s say someone has hypertension or diabetes or even gastrointestinal conditions. It’s not legal for [health coaches or nutritionists] in many states to intervene,” says Gabriela Barreto, MS, RD, CSSD.

A nutritionist can provide general dietary recommendations to people with uncomplicated health histories. And for people who need a little extra support as they attempt to shift their behaviors around food, a nutrition coach may offer the encouragement and accountability you need. But again, there’s no assurance that a nutritionist’s advice is backed by formal education or rooted in science.

How Dietitians Can Help Runners

“A dietitian is a board-certified expert on food and nutrition,” says Joanna Gregg, RD, Food Data Curator at MyFitnessPal. “Dietitians go through schooling to become experts on the science of food and how it affects human health. They’re trained in medical nutrition therapy and nutrition counseling for a wide range of demographics and can be certified further in a specialty such as sports, weight management, oncology, disordered eating, or pediatric nutrition.”

Dietitians who specifically work with runners help their clients improve their performance, train more effectively, and feel better during and after workouts. This often starts with fueling recommendations that are more personalized.

“A dietitian who understands energy output is going to listen to what you’re doing every day. They’re going to understand your speed and your distance and be able to estimate how much energy you’re using,” and, therefore, how many calories you need to consume, Barreto says. They can also monitor your progress, recognize trends you may not notice, and continually fine-tune your fueling strategies.

“We can also help with proper nutrient timing,” Spano says. Runners are more than familiar with prerace carbo-loading, but they often drop the ball during the recovery period when a bowl of pasta is less appealing. “Especially when it comes to an endurance-based athlete, that hour after training is a really pivotal time to get in nutrients,” Barreto says, noting that dietitians who work with athletes are well-versed in sports nutrition products and can pick the most appropriate drinks, shakes, gels, and bars based on their clients’ needs.

For some runners, fueling and nutrient timing aren’t their most pressing concerns. Both Spano and Barreto often work with athletes who have food fear or disordered eating habits, as well as other medical nutrition issues that can interfere with running. “We can also help with blood testing or other testing that may be needed to ensure that the individual is healthy,” Spano says.

What to Know Before Hiring a Dietitian

While hiring a dietitian is an investment, it could save you time and money in the long run.

There’s no shortage of free nutritional advice online, but culling through the clutter to find information that’s accurate and relevant to your body, sport, and personal goals is daunting. “You can spend all day on the internet looking up stuff, but it doesn’t mean that you can put it all together if you’re not an expert in that area,” Spano says.

Even the most nutrition-conscious runners make mistakes. Barreto notes that runners who use online activity calculators are often undereating by hundreds of calories, which leads to fatigue, headaches, and subpar performance.

Spano agrees that undereating is a common problem among runners, especially women. She also finds that runners who are hyper-focused on eating healthy foods are often consuming too much fiber, which can lead to gastrointestinal distress.

After consulting with a dietitian, you may also find that you’re spending money unnecessarily on nutrition-related products that you don’t actually need. “A sports dietitian can help with efficacious supplements. And it’s not just about which supplements work. Oftentimes, I’m weeding out things that don’t work,” Spano says. “So a runner might come to me, and I’ll say, ‘You don’t need to take this, this, and this.’ And they’re like, ‘Oh, thank god. I’m tired of doing this routine.’ So, we’re helping them save money and time and wasted effort.”

Tips for Hiring the Right Dietitian

Finding the right dietitian is a lot like finding the right doctor or therapist; some are more qualified than others, and it may take time to link up with a practitioner who feels like the right fit for you and your needs. Use these tips for a successful search.

Check Out EatRight.org

You can always Google “dietitians near me,” but if you want to narrow your search, check out the Academy of Nutrition and Dietetics’s online database of nutrition experts. You can search by location, specialty, and insurance, and each practitioner’s contact information and credentials are clearly listed.

Pay Attention to Credentials

Remember: There are no regulations for the terms “nutritionist” or “nutrition coach.” Look for a professional who’s a registered dietitian (RD) or certified nutrition specialist (CNS).

Pick a Sports Specialist

The scope of nutrition is broad, so dietitians tend to specialize in one area. Choose someone who, in addition to having RD or CNS in their title, also has CSSD, which stands for “certified specialist in sports dietetics.” This indicates that they’ve undergone additional training to work with athletes.

Do a Quick Interview

“Have a phone call. Talk to them and ask them how they work with clients, and tell them about your specific needs. Ask them about their experience,” Spano suggests. And make sure they understand your specific population, as the needs of an ultramarathoner will differ from those of a triathlete or someone who’s training for their first 10K.

“There are little ins and outs to every sport and population, even if you drill down to how you carry your gel packs. Somebody who knows the sport will understand what’s realistic in different situations,” Spano adds.