Impact of Ramadan Fasting on Dietary Intakes Among Healthy Adults: A Year-Round Comparative Study

Diet is a major lifestyle-related risk factor of various chronic diseases. Dietary intake can be assessed by subjective report and objective observation. Subjective assessment is possible using open-ended surveys such as dietary recalls or records, or using closed-ended surveys including food frequency questionnaires. Each method has inherent strengths and limitations. Continued efforts to improve the accuracy of dietary intake assessment and enhance its feasibility in epidemiological studies have been made. This article reviews common dietary assessment methods and their feasibility in epidemiological studies.

The US Department of Agriculture Automated Multiple-Pass Method (AMPM) is used for collecting 24-h dietary recalls in What We Eat In America, the dietary interview component of the National Health and Nutrition Examination Survey. Because the data have important program and policy applications, it is essential that the validity of the method be tested. The accuracy of the AMPM was evaluated by comparing reported energy intake (EI) with total energy expenditure (TEE) by using the doubly labeled water (DLW) technique. The 524 volunteers, aged 30-69 y, included an equal number of men and women recruited from the Washington, DC, area. Each subject was dosed with DLW on the first day of the 2-wk study period; three 24-h recalls were collected during the 2-wk period by using the AMPM. The first recall was conducted in person, and subsequent recalls were over the telephone. Overall, the subjects underreported EI by 11% compared with TEE. Normal-weight subjects [body mass index (in kg/m(2)) 30). Although the AMPM accurately reported EIs in normal-weight subjects, research is warranted to enhance its accuracy in overweight and obese persons.

Objective Independently of total caloric intake, a better quality of the diet (for example, conformity to the Mediterranean diet) is associated with lower obesity risk. It is unclear whether a brief dietary assessment tool, instead of full-length comprehensive methods, can also capture this association. In addition to reduced costs, a brief tool has the interesting advantage of allowing immediate feedback to participants in interventional studies. Another relevant question is which individual items of such a brief tool are responsible for this association. We examined these associations using a 14-item tool of adherence to the Mediterranean diet as exposure and body mass index, waist circumference and waist-to-height ratio (WHtR) as outcomes. Design Cross-sectional assessment of all participants in the “PREvención con DIeta MEDiterránea” (PREDIMED) trial. Subjects 7,447 participants (55–80 years, 57% women) free of cardiovascular disease, but with either type 2 diabetes or ≥3 cardiovascular risk factors. Trained dietitians used both a validated 14-item questionnaire and a full-length validated 137-item food frequency questionnaire to assess dietary habits. Trained nurses measured weight, height and waist circumference. Results Strong inverse linear associations between the 14-item tool and all adiposity indexes were found. For a two-point increment in the 14-item score, the multivariable-adjusted differences in WHtR were −0.0066 (95% confidence interval, –0.0088 to −0.0049) for women and –0.0059 (–0.0079 to –0.0038) for men. The multivariable-adjusted odds ratio for a WHtR>0.6 in participants scoring ≥10 points versus ≤7 points was 0.68 (0.57 to 0.80) for women and 0.66 (0.54 to 0.80) for men. High consumption of nuts and low consumption of sweetened/carbonated beverages presented the strongest inverse associations with abdominal obesity. Conclusions A brief 14-item tool was able to capture a strong monotonic inverse association between adherence to a good quality dietary pattern (Mediterranean diet) and obesity indexes in a population of adults at high cardiovascular risk.