What Is It?
How Does it Work?
What You Can Expect
Health Benefits
How To Choose a Practitioner
Evidence Based Rating Scale

What Is It?

A registered dietitian (R.D.) is a healthcare professional who has had an intensive university-based education and training in nutrition and food science. R.D.s perform nutritional assessments for individuals; design therapeutic diets for patients with specific illnesses; educate the public on diet and health; manage foodservice in hospitals and other health-care institutions (as well as in schools, hotels, and other public facilities); and conduct nutrition research. Many conventional and alternative health practitioners refer their patients to these experts for dietary counseling.

Although virtually anyone can adopt the title of "nutritionist," legal credentials and educational standards for R.D.s and other dietetics professionals are specific and comprehensive. These include, but are not limited to, the following:

Registered Dietitian (R.D.): R.D.s must earn a minimum of a B.A. degree at an accredited U.S. college or university, with coursework approved by the Commission on Accreditation for Dietetics Education (CADE) of the American Dietetics Association (ADA). They must also undergo a 6- to 12-month practice program or internship at a health-care facility, community agency, or foodservice corporation, or do the equivalent in combination with their undergraduate or graduate coursework. In addition, they must pass a national board examination administered by the Commission on Dietetic Registration (CDR).

Dietetic Technician, Registered (D.T.R.): A minimum of a two-year associate's or A.B. degree from an accredited U.S. college or university is required to become a D.T.R., in addition to the completion of a dietetics education program approved by the Commission on Accreditation for Dietetics Education (CADE). D.T.R.s must also perform 450 hours of supervised practice and pass a national written examination administered by the Commission on Dietetic Registration (CDR).

Board Certified Specialist in Pediatric Nutrition (C.S.P.): These specialists are R.D.s who have additional training and education in the nutritional needs of children. Board certification is granted in recognition of practice experience and completion of an exam that presents candidates with nine simulated clinical problems in pediatric nutrition.

Board Certified Specialist in Renal Nutrition (C.S.R.): A C.S.R is an R.D. with additional training and education in the nutritional needs of people who have kidney disease. As with C.S.P.s, board certification is granted in recognition of practice experience and successful completion of an exam simulating clinical problems.

Fellow of The American Dietetic Association (F.A.D.A.): Fellow certification is offered annually by the ADA to R.D.s who exhibit the characteristics of advanced-level practice. These include completion of the minimum of a Master's degree and eight years of work experience, as well as showing professional achievement. To become a fellow, the R.D. must have an approach to practice that reflects a global perspective, uses innovative and creative solutions, and values professional growth and self-knowledge.

How Does it Work?

Dietitians are skilled not only in the science of food and nutrition from a biological and physiological perspective, but they also apply principles from behavioral and social sciences. Therefore, they understand what our bodies need physically and emotionally to be healthier.

Dietitians promote optimal health, nutrition and well-being by helping patients learn to eat properly without compromising taste. If you want to learn more about nutrition, a dietitian can help you with everything from learning how to read labels at a supermarket and cooking healthy foods to choosing healthy meals at restaurants and resisting unhealthy temptations. If you need to gain or lose weight, a dietitian can tailor eating plans to your needs. Dietitians also can prepare individualized eating plans to help manage diabetes, digestive problems, eating disorders, high blood pressure, and other health concerns.

What You Can Expect

Before seeing a dietitian, get a check-up from your doctor so you know your current health stats, such as blood pressure and cholesterol levels. Along with this vital information, the dietitian will also want to know everything about your health, including what medications and supplements you take, what you eat, how much you exercise, etc. The more you tell the dietitian, the more help he or she will be.

The dietitian will prepare an eating plan based on the information you share and the reason for your visit. Together, you and the dietitian will come up with a comprehensive plan for you to take an active role in improving your health.

Health Benefits

A dietitian can be an integral part of a nutrition plan for patients with digestive problems, health issues, risk factors for diseases, and weight problems. 

Specifically, a dietitian may help you to: 

Manage high blood pressure. One of the most effective methods of treating mild to moderately high blood pressure is the Dietary Approaches to Stop Hypertension, or DASH diet, sponsored and researched by the National Institute of Health. The DASH diet, which has been shown to lower blood pressure in as little as two weeks, is based on eating a significant amount of low or non-fat dairy foods, whole grains, and fruits and vegetables. A 1999 clinical review of the DASH diet indicated use of the diet as a first-line treatment and alternative to drugs in treating high blood pressure, and the review also concluded following the diet may prevent hypertension, particularly in African Americans. (1) Another nutrition plan, called the Mediterranean diet, also has beneficial effects in lowering blood pressure. The plan relies on a high consumption of vegetables, fish, and most notably olive oil in order to lower blood pressure. A dietitian may be able to change your diet to lower blood pressure according to one of these plans.

Control weight. The most effective way to lose weight is to follow a healthy eating and exercising plan. If you want help choosing the best foods for your needs, a dietitian can tailor an eating plan that is right for you. A dietitian can help identify your common pitfalls and what you need to lose weight while still eating foods you enjoy. A dietitian also can help you create a daily, weekly or monthly plan to fit your schedule and ensure you are getting all the vitamins and minerals – and variety – you need to stick with the plan. A recent study found the effect of having a dietitian present during an outpatient visit with a physician is effective in achieving and maintaining weight loss. In the study of 80 overweight patients who were counseled to exercise 30 minutes a day and eat a modified DASH diet, 81 percent of the patients maintained significant weight loss (about 5 percent loss) over two years. The patients also had lower “bad” cholesterol, increased “good” cholesterol, and lower blood pressure after following the plan. (2) If you need to gain weight, a dietitian also can suggest calorie sources for healthy weight gain.

Manage diabetes. Diet alone can often be effective as the sole factor in treating and reversing type 2 diabetes and in improving blood glucose levels in both type 1 and type 2 diabetes. Because obesity is the major risk factor for type 2 diabetes, weight loss plays an important role in the cause, prevention and treatment. Dietitians understand how the two indices – glycemic index (GI) and glycemic load (GL) – play a role in a diabetic’s ability to manage blood glucose levels and achieve or maintain ideal body weight. Therefore, a dietitian can prepare a proper eating plan to treat diabetes. In a 2004 randomized, controlled trial of 147 obese patients with type 2 diabetes, patients received either dietitian-led lifestyle case management or educational material to manage the disease for a year. Those counseled by a dietitian reported greater weight loss, reduced waist circumference, reduced HbA(1c) levels, less use of prescription medications (primarily diabetes medications), and improved health-related quality of life compared with those who received educational material. (3) Another 2004 prospective, noncontrolled study involving 244 adults with type 2 diabetes who received nutrition counseling from RDs found ongoing intervention from dietitians improved symptoms of the disease. Increased time and/or number of sessions with the RDs resulted in weight loss, reduced glycosylated hemoglobin, fasting plasma glucose, total cholesterol, and triglyceride levels, particularly within the first three months of treatment. (4) Other studies have shown the same symptoms of diabetes are better controlled under the direction of a dietitian. (5)

Lower cholesterol. Cholesterol is in all foods derived from animal sources, so eating food with as little cholesterol and saturated fat as possible will help lower your cholesterol levels. Many people respond very well to cholesterol modifications through diet alone. A dietitian can help create a balanced healthful diet low in artery-clogging saturated and trans fats. Some studies even suggest that people who seek help from a nutritionist instead of their primary care physician alone fare better at lowering their cholesterol in the short to medium term. (6)

Eat after gastric bypass surgery. Gastric bypass surgery reduces the size of the stomach by creating two pouches connected to the intestines. Because the stomach then has a smaller capacity for food, it also has altered responses to food. Eating too much food too quickly can cause vomiting, damage to the staples from surgery, stretching of the pouches and obstruction of the stoma. After surgery, patients must learn to eat smaller meals and sip beverages slowly. A dietitian plays an important role in educating patients on learning to eat smaller portions and how to get the right amount of nutrients from those smaller servings. (7, 8)

Ease the stress of infertility. Nutrition is important for women trying to get pregnant. A dietitian can make sure women trying to get pregnant get the right nutrients and vitamins you and your baby need for a healthy pregnancy and to reduce the risk of birth defects. Also, it may be more difficult for women who are underweight or overweight to conceive. A dietitian can prescribe a sensible diet to help achieve a normal weight ideal for getting pregnant.

Treat eating disorders such as anorexia and bulimia. A dietitian can provide nutrition therapy to help normalize eating behaviors and nutritional status in patients with eating disorders such as anorexia nervosa and bulimia nervosa. (9) A 2002 outpatient group for patients with anorexia was developed and co-led by a dietitian and psychologist to help the patients gain weight through normalized eating. Significant changes were found in consumption of calories, fat and protein after eight weeks of group meetings and evaluation. This pilot study indicates the need for further research in this area. (10) 

How To Choose a Practitioner

Forty-one states require a license for the practice of dietetics. If a dietitian is practicing in a state that does not regulate the practice, that person should still have one of the above certifications, which are granted only by the American Dietetic Association/Commission on Dietetic Registration (ADA/CDR), which is the accrediting agency of the National Commission for Certifying Agencies (NCCA).

When you are looking for legitimate and responsible nutrition advice, always seek out a professional with evidence of appropriate training. R.D.s are not the same as Certified Nutritionists (see the WholeHealthMD Reference Library entry for Certified Nutritionist), although both have college degrees.


  • Because irresponsible advice on nutrition can be dangerous to your health, be very careful to ask specific questions and verify your dietitian’s education, training, professional credentials, and state license. 


    1. Sacks FM, Appel LJ, Moore TJ, et al. A dietary approach to prevent hypertension: a review of the Dietary Approaches to Stop Hypertension (DASH) Study. Clin Cardiol. 1999 Jul;22(7 Suppl)III6-10.

    2. Welty FK, Nasca MM, Lew NS, et al. Effect of onsite dietitian counseling on weight loss and lipid levels in an outpatient physician office. Am J Cardiol. 2007 Jul 1;100(1):73-5.

    3. Wolf AM, Conaway MR, Crowther JQ, et al. Translating lifestyle intervention to practice in obese patients with type 2 diabetes: Improving Control with Activity and Nutrition (ICAN) study. Diabetes Care. 2004 Jul;27(7):1570-6.

    4. Lemon CC, Lacey K, Lohse B, et al. Outcomes monitoring of health, behavior, and quality of life after nutrition intervention in adults with type 2 diabetes. J Am Diet Assoc. 2004 Dec;104(12):1805-15.

    5. National Institutes of Health (NIH) Publication No. 98-4083. Guidelines on the identification, evaluation, and treatment of overweight and obesity in adults: evidence report. Published by the National Heart, Lung, and Blood Institute and available at

    6. Thompson RL, Summerbell CD, Hooper L, et al. Dietary advice given by a dietitian versus other health professional or self-help resources to reduce blood cholesterol. The Cochrane Database of Systematic Reviews 2003, Issue 3. Art. No.: CD001366. DOI: 10.1002/14651858. CD001366.

    7. Priddy ML, Gastric reduction surgery: a dietitian’s experience and perspective. J Am Diet Assoc. 1985 Apr;85(4):455-9.

    8. Bukoff M, Carlson S. Diet modifications and behavioral changes for bariatric gastric surgery. J Am Diet Assoc. 1981 Feb;78(2):158-61.

    9. American Dietetic Association. Position of the American Dietetic Association: Nutrition intervention in the treatment of anorexia nervosa, bulimia nervosa, and other eating disorders. J Am Diet Assoc. 2006 Dec;106(12):2073-82.

    10.Waisberg JL, Woods MT. A nutrition and behaviour change group for patients with anorexia nervosa. Can J Diet Pract Res. 2002 Winter;63(4):202-5. 

    Evidence Based Rating Scale 

    The Evidence Based Rating Scale is a tool that helps consumers translate the findings of medical research studies with what our clinical advisors have found to be efficacious in their personal practice. This tool is meant to simplify which supplements demonstrate promise in the treatment of certain conditions. This scale does not take into account any possible interactions with any medication/ condition/ or therapy you may be currently undertaking. It is therefore advisable to ask your doctor before starting any new treatment regimen.




     Celiac Disease




     Several studies indicate efficacy in educating patients

    about and providing resources for adherence to

    gluten-free diet.





















    Meta-analyses and randomized controlled trials have proven efficacy for nutritional management of diabetes and obesity in both the short and long term.





    Eating disorders






    Preliminary evidence indicates efficacy. More research is needed.

    Date Published: 04/19/2005

    Previous  |  Next
    > Printer-friendly Version

    © 2000- 2019 ., LLC. 21251 Ridgetop Circle, Suite 150, Sterling, VA 20166. All rights reserved. Reproduction in whole or in part without permission is prohibited. Privacy Policy

    Disclaimer: All material provided in the WholeHealthMD website is provided for educational purposes only. Consult your physician regarding the applicability of any information provided in the WholeHealthMD website to your symptoms or medical condition.