Victoria J. Burley

Development, validation and utilisation of food-frequency questionnaires – a review

OBJECTIVE The purpose of this review is to provide guidance on the development, validation and use of food-frequency questionnaires (FFQs) for different study designs. It does not include any recommendations about the most appropriate method for dietary assessment (e.g. food-frequency questionnaire versus weighed record). METHODS A comprehensive search of electronic databases was carried out for publications from 1980 to 1999. Findings from the review were then commented upon and added to by a group of international experts. RESULTS Recommendations have been developed to aid in the design, validation and use of FFQs. Specific details of each of these areas are discussed in the text. CONCLUSIONS FFQs are being used in a variety of ways and different study designs. There is no gold standard for directly assessing the validity of FFQs. Nevertheless, the outcome of this review should help those wishing to develop or adapt an FFQ to validate it for its intended use.

Adherence to a Smartphone Application for Weight Loss Compared to Website and Paper Diary: Pilot Randomized Controlled Trial

Background There is growing interest in the use of information communication technologies to treat obesity. An intervention delivered by smartphone could be a convenient, potentially cost-effective, and wide-reaching weight management strategy. Although there have been studies of texting-based interventions and smartphone applications (apps) used as adjuncts to other treatments, there are currently no randomized controlled trials (RCT) of a stand-alone smartphone application for weight loss that focuses primarily on self-monitoring of diet and physical activity. Objective The aim of this pilot study was to collect acceptability and feasibility outcomes of a self-monitoring weight management intervention delivered by a smartphone app, compared to a website and paper diary. Methods A sample of 128 overweight volunteers were randomized to receive a weight management intervention delivered by smartphone app, website, or paper diary. The smartphone app intervention, My Meal Mate (MMM), was developed by the research team using an evidence-based behavioral approach. The app incorporates goal setting, self-monitoring of diet and activity, and feedback via weekly text message. The website group used an existing commercially available slimming website from a company called Weight Loss Resources who also provided the paper diaries. The comparator groups delivered a similar self-monitoring intervention to the app, but by different modes of delivery. Participants were recruited by email, intranet, newsletters, and posters from large local employers. Trial duration was 6 months. The intervention and comparator groups were self-directed with no ongoing human input from the research team. The only face-to-face components were at baseline enrollment and brief follow-up sessions at 6 weeks and 6 months to take anthropometric measures and administer questionnaires. Results Trial retention was 40/43 (93%) in the smartphone group, 19/42 (55%) in the website group, and 20/43 (53%) in the diary group at 6 months. Adherence was statistically significantly higher in the smartphone group with a mean of 92 days (SD 67) of dietary recording compared with 35 days (SD 44) in the website group and 29 days (SD 39) in the diary group (P<.001). Self-monitoring declined over time in all groups. In an intention-to-treat analysis using baseline observation carried forward for missing data, mean weight change at 6 months was -4.6 kg (95% CI –6.2 to –3.0) in the smartphone app group, –2.9 kg (95% CI –4.7 to –1.1) in the diary group, and –1.3 kg (95% CI –2.7 to 0.1) in the website group. BMI change at 6 months was –1.6 kg/m2 (95% CI –2.2 to –1.1) in the smartphone group, –1.0 kg/m2 (95% CI –1.6 to –0.4) in the diary group, and –0.5 kg/m2 (95% CI –0.9 to 0.0) in the website group. Change in body fat was –1.3% (95% CI –1.7 to –0.8) in the smartphone group, –0.9% (95% CI –1.5 to –0.4) in the diary group, and –0.5% (95% CI –0.9 to 0.0) in the website group. Conclusions The MMM app is an acceptable and feasible weight loss intervention and a full RCT of this approach is warranted. Trial Registration ClinicalTrials.gov NCT01744535; http://clinicaltrials.gov/ct2/show/NCT01744535 (Archived by WebCite at http://www.webcitation.org/6FEtc3PVB)

The specificity of satiety: The influence of foods of different macronutrient content on the development of satiety

The effects of consuming equicaloric preloads with different macronutrient contents on the development of satiety were investigated. Ten normal-weight, nondieting women fasted overnight and then rated hunger, fullness, and food preferences, and the pleasantness of the taste of food samples before and after five different preloads. The greatest changes in the pleasantness of the taste of the food occurred for the eaten food relative to the uneaten food. Macronutrient content of the preloads did not significantly influence the magnitude of these changes or the pleasantness of foods with similar nutrient contents. Therefore, no evidence of nutrient-specificity was obtained. Nutrient composition had a differential effect on hunger, fullness and food intake. Ratings of hunger decreased and fullness increased following the high starch and high protein preloads to a greater extent than after the high fat, high sucrose and mixed content preloads. When a self-selection meal was offered 2 hours after the preloads energy intake and preference for high carbohydrate and high fat food items were significantly decreased by the high protein and high starch preloads. However, no specific reduction in macronutrient intake was observed. In conclusion, differential effects of the preloads were observed in subjective ratings of hunger, fullness, preferences and subsequent food intake, but there was no indication that satiety was macronutrient-specific.

Food-frequency questionnaires: a review of their design, validation and utilisation

A review of the literature concerning the design, utilisation and validation of food-frequency questionnaires (FFQ) has been carried out using a semi-systematic approach to obtaining, reviewing and extracting data from articles. Databases were searched from 1980 to 1999. The present review identified 227 validation (from 1980 to September 1999) and 164 utilisation (for 1998 only) studies. A number of design issues have been evaluated through the present review. These include: the need to consider how portion sizes have been described, self-defined giving higher mean correlations; how an FFQ was administered, interviewer-administered giving higher mean correlations for some nutrients; how many items to include on an FFQ, those with the largest number of items having higher correlations. Validation techniques were described. Most validation studies involved comparing an FFQ against another dietary assessment method; only 19 % compared an FFQ to a biomarker. Measurement differences were most commonly assessed by correlation coefficients as opposed to other more appropriate methods. Mean correlation coefficients were highest for Ca and fat, and lowest for vitamin A and vegetables. The utilisation studies showed that FFQ were most commonly used in cross-sectional surveys, with ninety-three of the FFQ being designed to be disease-specific. The present review results were presented to a group of experts and a consensus arrived at concerning the development, validation and use of FFQ. Recommendations derived from the consensus arising from the literature review are presented as an appendix to the present paper.

Dietary fat and the control of energy intake: evaluating the effects of fat on meal size and postmeal satiety.

Three separate experiments in lean subjects confirmed that a 1.52-MJ (362-kcal) carbohydrate supplement at breakfast suppressed appetite 90 min later but had no effect on a test meal given after 270 min. A 1.52-MJ (362-kcal) fat supplement produced no detectable action on measures of appetite at any time point. Therefore, fat and carbohydrate do not have identical effects on the appetite profile. In a further study in obese subjects, a novel experimental design was used to assess the satiating efficiency and compensatory response of fat. Eating from a range of either high-fat or high-carbohydrate foods, obese subjects voluntarily consumed twice as much energy from the fat items, thereby indicating a weak action of fat on satiation. In turn, this large intake of fat exerted a disproportionately weak effect on satiety. These studies suggest that the appetite-control system may have only weak inhibitory mechanisms to prevent the passive overconsumption of dietary fat. The results indicate how this action could induce a positive energy balance and lead to a gradual upward drift in body mass index.

Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis

Objective To investigate dietary fibre intake and any potential dose-response association with coronary heart disease and cardiovascular disease. Design Systematic review of available literature and dose-response meta-analysis of cohort studies using random effects models. Data sources The Cochrane Library, Medline, Medline in-process, Embase, CAB Abstracts, ISI Web of Science, BIOSIS, and hand searching. Eligibility criteria for studies Prospective studies reporting associations between fibre intake and coronary heart disease or cardiovascular disease, with a minimum follow-up of three years and published in English between 1 January 1990 and 6 August 2013. Results 22 cohort study publications met inclusion criteria and reported total dietary fibre intake, fibre subtypes, or fibre from food sources and primary events of cardiovascular disease or coronary heart disease. Total dietary fibre intake was inversely associated with risk of cardiovascular disease (risk ratio 0.91 per 7 g/day (95% confidence intervals 0.88 to 0.94)) and coronary heart disease (0.91 (0.87 to 0.94)). There was evidence of some heterogeneity between pooled studies for cardiovascular disease (I2=45% (0% to 74%)) and coronary heart disease (I2=33% (0% to 66%)). Insoluble fibre and fibre from cereal and vegetable sources were inversely associated with risk of coronary heart disease and cardiovascular disease. Fruit fibre intake was inversely associated with risk of cardiovascular disease. Conclusions Greater dietary fibre intake is associated with a lower risk of both cardiovascular disease and coronary heart disease. Findings are aligned with general recommendations to increase fibre intake. The differing strengths of association by fibre type or source highlight the need for a better understanding of the mode of action of fibre components.

Dietary Fiber and Colorectal Cancer Risk: A Nested Case–Control Study Using Food Diaries

BACKGROUND Results of epidemiological studies of dietary fiber and colorectal cancer risk have not been consistent, possibly because of attenuation of associations due to measurement error in dietary exposure ascertainment. METHODS To examine the association between dietary fiber intake and colorectal cancer risk, we conducted a prospective case-control study nested within seven UK cohort studies, which included 579 case patients who developed incident colorectal cancer and 1996 matched control subjects. We used standardized dietary data obtained from 4- to 7-day food diaries that were completed by all participants to calculate the odds ratios for colorectal, colon, and rectal cancers with the use of conditional logistic regression models that adjusted for relevant covariates. We also calculated odds ratios for colorectal cancer by using dietary data obtained from food-frequency questionnaires that were completed by most participants. All statistical tests were two-sided. RESULTS Intakes of absolute fiber and of fiber intake density, ascertained by food diaries, were statistically significantly inversely associated with the risks of colorectal and colon cancers in both age-adjusted models and multivariable models that adjusted for age; anthropomorphic and socioeconomic factors; and dietary intakes of folate, alcohol, and energy. For example, the multivariable-adjusted odds ratio of colorectal cancer for highest vs the lowest quintile of fiber intake density was 0.66 (95% confidence interval = 0.45 to 0.96). However, no statistically significant association was observed when the same analysis was conducted using dietary data obtained by food-frequency questionnaire (multivariable odds ratio = 0.88, 95% confidence interval = 0.57 to 1.36). CONCLUSIONS Intake of dietary fiber is inversely associated with colorectal cancer risk. Methodological differences (ie, study design, dietary assessment instruments, definition of fiber) may account for the lack of convincing evidence for the inverse association between fiber intake and colorectal cancer risk in some previous studies.

The time course of sensory-specific satiety

The time course of the changes in hedonic response following ingestion of three different foods was investigated. Normal weight, non-dieting female subjects rated the pleasantness of the appearance, smell, texture and taste of nine foods and then consumed as much as they wanted of cheese on cracker, tomato soup or orange jello. After this first course, subjects re-rated the pleasantness of the foods at 2, 20, 40 and 60 min. Following the 60 min rating, subjects were offered a second course of cheese on cracker or chocolate bar. For all sensory variables measured and for all foods consumed, the greatest decline in pleasantness occurred for the eaten food 2 min after consumption. For the food rate as most palatable (cheese on cracker) there was some recovery of pleasantness of the texture and taste over the hour. Intake in the second course was similar regardless of whether the food offered was different or the same as the food consumed in the first course. Since changes in the pleasantness of the foods occurred rapidly for all sensory variables studied and since the magnitude of these changes did not increase over time, it is concluded that the development of sensory-specific satiety is related primarily to the sensory stimulation accompanying ingestion as opposed to the postabsorptive effects of consuming these foods.

Evidence of high sugar intake, and low fibre and mineral intake, in the gluten-free diet

Aliment Pharmacol Ther 2010; 32: 573–581

Meat consumption and risk of breast cancer in the UK Women's Cohort Study

We performed a survival analysis to assess the effect of meat consumption and meat type on the risk of breast cancer in the UK Womens Cohort Study. Between 1995 and 1998 a cohort of 35 372 women was recruited, aged between 35 and 69 years with a wide range of dietary intakes, assessed by a 217-item food frequency questionnaire. Hazard ratios (HRs) were estimated using Cox regression adjusted for known confounders. High consumption of total meat compared with none was associated with premenopausal breast cancer, HR=1.20 (95% CI: 0.86–1.68), and high non-processed meat intake compared with none, HR=1.20 (95% CI: 0.86–1.68). Larger effect sizes were found in postmenopausal women for all meat types, with significant associations with total, processed and red meat consumption. Processed meat showed the strongest HR=1.64 (95% CI: 1.14–2.37) for high consumption compared with none. Women, both pre- and postmenopausal, who consumed the most meat had the highest risk of breast cancer.