What is the question?

• The question is: What is the relationship between the frequency of eating and risk of cardiovascular disease?

What is the answer to the question?

• Insufficient evidence is available to determine the relationship between the frequency of eating and cardiovascular disease.

Why was this question asked?

• This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee.

How was this question answered?

• The 2020 Dietary Guidelines Advisory Committee, Frequency of Eating Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team.
• Frequency of eating was defined as the number of daily eating occasions.

What is the population of interest? 

• The population of interest was generally healthy children through older adults (ages 2 and older). 

What evidence was found? 

• This review identified 2 articles that met the inclusion criteria. 
• Inconsistent results from 2 prospective cohort studies with critical limitations, were insufficient to draw conclusions. 

How up-to-date is this systematic review?

• This review searched for studies from January 2000 to September 2019.

Background 

• This important public health question was identified by the U.S. Departments of Agriculture (USDA) and Health and Human Services (HHS) to be examined by the 2020 Dietary Guidelines Advisory Committee.
• The 2020 Dietary Guidelines Advisory Committee, Frequency of Eating Subcommittee conducted a systematic review to answer this question with support from the Nutrition Evidence Systematic Review (NESR) team.
• The goal of this systematic review was to examine the following question: What is the relationship between the frequency of eating and risk of cardiovascular disease?

Conclusion statement and grade

• Insufficient evidence is available to determine the relationship between the frequency of eating and cardiovascular disease. (Grade: Grade not assignable)

Methods 

• Literature search was conducted using 4 databases (PubMed, Cochrane, Embase, and CINAHL) to identify articles that evaluated an intervention or exposure of the frequency of eating and the outcome of cardiovascular disease. A manual search was also conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two authors independently for inclusion based on pre-determined criteria. 
• Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The Committee qualitatively synthesized the body of evidence to inform development of a conclusion statement(s), and graded the strength of evidence using pre-established criteria for risk of bias, consistency, directness, precision, and generalizability.

Summary of the evidence

• This systematic review was undertaken to examine the relationship between the frequency of eating and cardiovascular disease. 
• This review identified 2 prospective cohort studies published between January, 2000 and September, 2019 that met the inclusion criteria for this systematic review.
• The studies were inconsistent in terms of how they defined and examined frequency of eating, the outcomes they examined, and in their reported results:
  • One included study reported that a higher eating frequency at baseline was associated with lower blood pressure after a 5-year follow-up. 
  • One included study reported no association between eating frequency at baseline and risk of coronary heart disease after a 16-year follow-up.
• Critical limitations were identified within the body of evidence:
  • Weak study designs were used to explore this question.
  • Eating frequency was measured only at baseline, leading to concern that changes in exposure status may have occurred over the follow-up time periods.
  • The amount of attrition was unknown.
  • The study showed several risks of bias.
  • Inconsistent outcomes were included across studies with respect to relative risks and 95% confidence intervals for CHD, systolic blood pressure, diastolic blood pressure, and hypertension.
  • Water consumption was not explicitly mentioned in either included study.
• Due to the small body of evidence with inconsistency in design and reported results and several limitations, the Committee determined that the evidence was insufficient to draw conclusions about the relationship between frequency of eating and cardiovascular disease.