Guideline development process

Publication Details

This guideline was developed in accordance with the WHO evidence-informed guideline development procedures outlined in the WHO Handbook for guideline development (8).

Advisory groups

Development of this guideline was undertaken by the WHO Department of Nutrition for Health and Development1, in partnership with the Department of Research Policy and Cooperation and members of the WHO Secretariat (Annex 3). The work was guided by the WHO Steering Committee for Nutrition Guideline Development (Annex 4), which also provided overall supervision of the guideline development process. The WHO Secretariat and the Steering Committee included representatives from all departments of WHO with an interest in the provision of scientific advice on nutrition. Two additional groups were formed: an advisory guideline group and an external expert and stakeholder panel, as outlined below.

Advisory guideline group

The WHO Nutrition Guidance Expert Advisory Group (NUGAG) Subgroup on Diet and Health was convened to support the development of this guideline (Annex 5). This group included experts who had previously participated in various WHO expert advisory panels, as well as others identified through open calls for specialists. In forming this group, WHO took into consideration the need for a balanced gender mix, expertise from multiple disciplinary areas and representation from all WHO regions. Efforts were made to include subject-matter experts; statistical, systematic review, program evaluation and Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodologists; and representatives of potential stakeholders (e.g. programme managers and other health professionals involved in the health-care process). There were no representatives of commercial organizations, because such individuals are prohibited from being members of any WHO guideline group. External resource persons, including subject matter experts and systematic review and GRADE methodologists, were invited to the NUGAG meetings as observers to provide technical input. These individuals did not participate in the decision-making processes. NUGAG’s role was to advise WHO on the choice of outcomes important for decision-making and the interpretation of the evidence.


The External Expert and Stakeholder Panel was formed during the planning stages of guideline development. The panel was consulted on the scope of the guideline, and on the specific research questions to be addressed and outcomes to be investigated in the systematic reviews of the literature. The panel was later asked to review and provide feedback on the completed draft guideline (Annex 6). During the consultations on both the scoping of the guidelines and the draft guideline documents, there was an open call for all interested parties to join the External Expert and Stakeholder Panel. The panel comprises individuals who responded to direct solicitation for contributions based on their known expertise and interest in the subject matter, or to the WHO open call for public comment executed through the electronic mailing lists of the WHO Department of Nutrition for Health and Development, and that of the Codex Alimentarius Commission, and through the posting of the call for public comment on the WHO and United Nations (UN) Standing Committee of Nutrition websites.

Scoping of the guideline, evidence appraisal and decision-making

WHO developed an initial set of questions to be addressed in the guideline. The questions were based on the needs of Member States and international partners for policy and programme guidance. They were also influenced by the request of the Codex Committee of Nutrition and Foods for Special Dietary Uses. The population, intervention, control and outcomes (PICO) format was used in generating the questions (Annex 7). The PICO questions were first discussed and reviewed by the WHO Secretariat and the WHO Steering Committee for Nutrition Guideline Development and were then made available for public comment from 1 to 28 February 2011. Feedback was received from 16 individuals or organizational stakeholders, and the questions were adapted accordingly.

The draft set of PICO questions was presented to the NUGAG Subgroup on Diet and Health during its meeting on 14–18 March 2011. During that meeting, the guideline topic was introduced and the scope of the guideline to be generated finalized. The PICO questions were discussed and outcomes and populations were ranked in importance by NUGAG members. The prioritization of the PICO questions defined the scope of the evidence to be used in informing the guideline development. Subsequent to the meeting, WHO reviewed the scientific literature and conducted new systematic reviews and meta-analyses to address the PICO questions. WHO was supported in the execution of these reviews by external experts with subject-matter expertise, and expertise in systematic reviews and the GRADE methodology.

A follow-up meeting of the NUGAG Subgroup on Diet and Health was held from

29 November to 2 December 2011. WHO presented the systematic reviews of evidence, and a draft recommendation that had been prepared before the meeting. This draft recommendation included:

  • a summary of the evidence from the systematic reviews;
  • draft GRADE evidence profiles assessing the quality of the body of evidence;
  • potential research gaps, concerns and opportunities for feasible implementation of the recommendations in diverse cultural contexts;
  • appropriate references.

The NUGAG Subgroup on Diet and Health discussed the evidence and the GRADE assessment of the quality of evidence, and advised WHO on the interpretation of the results. The subgroup also discussed the draft recommendation and, through consensus, reached an agreement on that recommendation.

The systematic reviews and the GRADE evidence profiles for each of the critical outcomes were used for drafting the guideline. Classification of the strength of each recommendation included consideration of the desirable and undesirable effects of the recommendation, the overall quality of the evidence, values and preferences related to the recommendation in different settings, and the cost of options available to public health authorities in implementing the recommendation in different settings (Annex 8). The classification was discussed among the NUGAG members, invited external resource persons and the members of the WHO Secretariat present at the meeting. The final wording of the recommendations and their strength were based on the consensus of members of the WHO Secretariat present and the NUGAG members only. There were no strong disagreements among the NUGAG members.

From 1 to 29 February 2012, a draft of this guideline was made available for public comment. Participants in the External Expert and Stakeholder Panel were consulted, and other interested parties were invited to comment, as outlined above. More than

165 comments were received from 30 individuals and representatives of stakeholder groups. WHO reviewed the comments and made appropriate updates to the guideline. The guideline was then presented for finalization to the NUGAG Subgroup on Diet and Health at their meeting on 27–30 March 2012. The finalized guideline was submitted for clearance by WHO before publication.

Management of conflicts of interest

According to the rules in the WHO Basic documents (47), all experts participating in WHO meetings must declare any interest relevant to the meeting before participating. The declaration of interest forms for all guideline group members were reviewed by WHO when finalizing the composition of the NUGAG Subgroup on Diet and Health. All NUGAG members, external experts and other special invitees participating in each of the NUGAG meetings submitted a declaration of interests form, together with their curriculum vitae. In addition, each participant verbally declared interests at the beginning of each meeting. The procedures for management of interests strictly followed the WHO Guidelines for declaration of interests for WHO experts (48). The potential interests declared by members of the NUGAG Subgroup on Diet and Health and external expert and resource persons are summarized in Annex 9.



The Department of Research Policy and Cooperation has since been reorganized and the nutrition guideline development work is being carried out in close collaboration with the Department of Knowledge Management and Sharing.