Note from the US Preventive Services Task Force (USPSTF) and the National Guideline Clearinghouse: In updating its recommendations, the USPSTF did not reevaluate the benefits of a healthy diet, which are detailed in many other reports. Instead, it focused on new controlled studies of the efficacy of counseling for changing dietary behavior in patients similar to those found in primary care practices. The review did not include studies of dietary interventions for specific chronic illnesses (eg, heart disease, diabetes, renal failure) but included studies enrolling patients with common risk factors such as elevated cholesterol, hypertension, obesity, or family history of heart disease. Counseling interventions with a primary focus on weight loss, weight management, and/or the treatment of obesity are covered in a separate review and are outside the scope of this recommendation. Studies of diet interventions focusing on lowering cholesterol levels in patients with elevated cholesterol or other lipid abnormalities are addressed in a separate USPSTF report entitled Screening for Lipid Disorders in Adults available from the USPSTF Web site. Studies of breastfeeding will also be addressed in a future USPSTF report.
The U.S. Preventive Services Task Force (USPSTF) grades its recommendations (A, B, C, D, or I) and the quality of the overall evidence for a service (good, fair, poor). The definitions of these grades can be found at the end of the "Major Recommendations" field.
- The U.S. Preventive Services Task Force (USPSTF) concludes that the evidence is insufficient to recommend for or against routine behavioral counseling to promote a healthy diet in unselected patients in primary care settings. I recommendation.
The USPSTF found fair evidence that brief, low- to medium-intensity behavioral dietary counseling in the primary care setting can produce small to medium changes in average daily intake of core components of an overall healthy diet (especially saturated fat and fruit and vegetables) in unselected patients (see the "Scientific Evidence" section of the original guideline document for discussion of patient populations and intensity of interventions). The strength of this evidence, however, is limited by reliance on self-reported diet outcomes, limited use of measures corroborating reported changes in diet, limited follow-up data beyond 6 to 12 months, and enrollment of study participants who may not be fully representative of primary care patients. In addition, there is limited evidence to assess possible harms (see "Clinical Considerations" below). As a result, the USPSTF concluded that there is insufficient evidence to determine the significance and magnitude of the benefit of routine counseling to promote a healthy diet in adults. Although community-based studies have evaluated measures to reduce dietary fat intake in children, no controlled trials of routine behavioral dietary counseling for children or adolescents in the primary care setting were identified.
- The USPSTF recommends intensive behavioral dietary counseling for adult patients with hyperlipidemia and other known risk factors for cardiovascular and diet-related chronic disease. Intensive counseling can be delivered by primary care clinicians or by referral to other specialists, such as nutritionists or dietitians. B recommendation.
The USPSTF found good evidence that medium- to high-intensity counseling interventions can produce medium to large changes in average daily intake of core components of a healthy diet (including saturated fat, fiber, fruit, and vegetables) among adult patients at increased risk for diet-related chronic disease. Intensive counseling interventions that have been examined in controlled trials among at-risk adult patients have combined nutrition education with behavioral dietary counseling provided by a nutritionist, dietitian, or specially trained primary care clinician (e.g., physician, nurse, or nurse practitioner). The USPSTF concluded that such counseling is likely to improve important health outcomes and that benefits outweigh potential harms. No controlled trials of intensive counseling in children or adolescents that measured diet were identified.
Clinical Considerations
- Several brief dietary assessment questionnaires have been validated for use in the primary care setting. These instruments can identify dietary counseling needs, guide interventions, and monitor changes in patients’ dietary patterns. However, these instruments are susceptible to the bias of the respondent. Therefore, when used to evaluate the efficacy of counseling, efforts to verify self-reported information are recommended since patients receiving dietary interventions may be more likely to report positive changes in dietary behavior than control patients.
- Effective interventions combine nutrition education with behaviorally-oriented counseling to help patients acquire the skills, motivation, and support needed to alter their daily eating patterns and food preparation practices. Examples of behaviorally-oriented counseling interventions include teaching self-monitoring, training to overcome common barriers to selecting a healthy diet, helping patients to set their own goals, providing guidance in shopping and food preparation, role playing, and arranging for intra-treatment social support. In general, these interventions can be described with reference to the 5-A behavioral counseling framework: Assess dietary practices and related risk factors, Advise to change dietary practices, Agree on individual diet change goals, Assist to change dietary practices or address motivational barriers, and Arrange regular
follow-up and support or refer to more intensive behavioral nutritional
counseling (e.g., medical nutrition therapy) if needed.
- Two approaches appear promising for the general
population of adult patients in primary care settings: (1) medium-intensity
face-to-face dietary counseling (two to three group or individual sessions)
delivered by a dietitian or nutritionist or by a specially trained primary
care physician or nurse practitioner, and (2) lower-intensity interventions
that involve 5 minutes or less of primary care provider counseling
supplemented by patient self-help materials, telephone counseling, or other
interactive health communications. However, more research is needed to assess
the long-term efficacy of these treatments and the balance of benefits and
harms.
- The largest effect of dietary counseling in
asymptomatic adults has been observed with more intensive interventions
(multiple sessions lasting 30 minutes or longer) among patients with
hyperlipidemia or hypertension, and among others at increased risk for
diet-related chronic disease. Effective interventions include individual or
group counseling delivered by nutritionists, dietitians, or specially trained
primary care practitioners or health educators in the primary care setting or
in other clinical settings by referral. Most studies of these interventions
have enrolled selected patients, many of whom had known diet-related risk
factors such as hyperlipidemia or hypertension. Similar approaches may be
effective with unselected adult patients, but adherence to dietary advice may
be lower, and health benefits smaller, than in patients who have been told
they are at higher risk for diet-related chronic disease.
- Office-level systems supports (prompts, reminders,
and counseling algorithms) have been found to significantly improve the
delivery of appropriate dietary counseling by primary care clinicians.
- Possible harms of dietary counseling have not been well defined or measured. Some have raised concerns that if patients focus only on reducing total fat intake without attention to reducing caloric intake, an increase in carbohydrate intake (e.g., reduced-fat or low-fat food products) may lead to weight gain, elevated triglyceride levels, or insulin resistance. Nationally, obesity rates have increased despite declining fat consumption, but studies did not consistently examine effects of counseling on outcomes such as caloric intake and weight.
- Little is known about effective dietary counseling for children or adolescents in the primary care setting. Most studies of nutritional interventions for children and adolescents have focused on non-clinical settings (such as schools) or have used physiologic outcomes such as cholesterol or weight rather than more comprehensive measures of a healthy diet.
Definitions
USPSTF grades its recommendations according to one of 5 classifications (A, B, C, D, I) reflecting the strength of evidence and magnitude of net benefit (benefits minus harms).
A
The USPSTF strongly recommends that clinicians provide [the service] to eligible patients. The USPSTF found good evidence that [the service] improves important health outcomes and concludes that benefits substantially outweigh harms.
B
The USPSTF recommends that clinicians provide [this service] to eligible patients. The USPSTF found at least fair evidence that [the service] improves important health
outcomes and concludes that benefits outweigh harms.
C
The USPSTF makes no recommendation for or against routine provision of [the service]. The USPSTF found at least fair evidence that [the service] can improve health outcomes but concludes
that the balance of benefits and harms is too close to justify a general recommendation.
D
The USPSTF recommends against routinely providing [the service] to asymptomatic patients. The USPSTF found at least fair evidence that [the service] is ineffective or that harms outweigh
benefits.
I
The USPSTF concludes that the evidence is insufficient to recommend for or against routinely providing [the service]. Evidence that [the service] is effective is lacking, of poor
quality, or conflicting and the balance of benefits and harms cannot be determined.
The U.S. Preventive Services Task Force (USPSTF) grades the quality of the overall evidence for a service on a 3-point scale (good, fair, poor).
Good
Evidence includes consistent results from well-designed, well-conducted studies in representative populations that directly assess effects on health outcomes.
Fair
Evidence is sufficient to determine effects on health outcomes, but the strength of the evidence is limited by the number,
quality, or consistency of the individual studies, generalizability to routine practice, or indirect nature of the evidence on health outcomes.
Poor
Evidence is insufficient to assess the effects on health outcomes because of limited number or power of studies, important flaws in their design or conduct, gaps in the chain of evidence, or lack of
information on important health outcomes.
