The next time your personal trainer tries to sell you on a new protein powder or diet plan, hit pause—you should’t take nutrition advice from a trainer if they’re not properly licensed. While a trainer’s suggestions might come with the best intentions, nutrition counseling and personalized meal planning should be left to the professionals.

“Practicing trainers interested in using nutrition tools are subject to the statutes of the relevant nutrition laws for their state,” according to the American Nutrition Association. “In a state with an exclusive scope of practice nutrition law, it is illegal for a personal trainer/fitness coach without a nutrition/dietetics license to use nutrition tools in their work unless the practitioner’s nutrition guidance is covered under an exemption to the nutrition/dietetics licensing law.”

The laws vary by state. For example, in Tennessee, an athletic trainer or coach cannot legally give nutrition counseling if they’re not properly licensed. In Arizona, however, there is no legal recourse for providing nutrition counseling without a license.

That said, of your unlicensed personal trainer offers you a protein bar, they’re unlikely to face legal recourse. Trainers may talk to their clients about basic nutrition without a specific license—they just have to know their limits, says Lindsay Ogden, a certified personal trainer, nutrition coach, and small-group program training manager at Life Time.

“In most places, trainers can talk generally about nutrition for supporting broad health and fitness goals for otherwise healthy clients,” Ogden says. “Registered dietitians earn a degree and pass a licensure exam that qualifies them to offer medical nutritional therapy—treating medical conditions such as diabetes or obesity. Unless you’re a registered dietitian, it’s best to avoid treating, prescribing, and diagnosing. In some states, even giving someone a meal plan is considered ‘prescribing’ and not allowed unless you’re an RD.”

Your coach might encourage you to drink some water post-workout, and that’s okay. But say, for example, they advise you to adopt a plant-based diet to help treat underlying health conditions, that’s not.

Instead of going state-by-state to learn the rules, your best bet is to hire a personal trainer or athletic coach who is also formally educated on diet and nutrition. After all, food is vital for healthy fitness—it’s literally fuel for the body that directly affects performance and recovery.

“The best fitness professionals seek certifications to educate themselves and help guide clients,” says Ogden. “If your trainer is not an RD or a certified nutrition noach, I would recommend you seek that separately from your training sessions.”

Michelle Gottfried, MS, CNS, lead nutritionist at the Nutritional Genomics Institute, agrees with Ogden that trainers and dietitians can work in tandem to better support their clients.

“Because nutrition involves the biochemistry of the body, it’s important that if a trainer is giving nutrition advice… about a specific diet or supplement that they do have the appropriate classes in biochemistry,” Gottfried says. “If a nutritionist is prescribing specific exercises beyond general recommendations that they have the appropriate credentials to be able to advise a client on how best to do that particular exercise so they are not injured. Having someone who has the appropriate education in both of these is ideal.”

Next time you’re on the market for a personal trainer, make sure their resume includes dietary certifications. Or seek nutritional advice from another expert who can work with your uncertified athletic trainer. Keeping trainers and nutritionists in their own lanes is meant to help you achieve the best results.

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