Date Published: February 26, 2018
Publisher: Oxford University Press
Author(s): Natalie Teasdale, Ahmed Elhussein, Frances Butcher, Carmen Piernas, Gill Cowburn, Jamie Hartmann-Boyce, Rhea Saksena, Peter Scarborough.
Self-monitoring (SM) of diet and tailored feedback (TF) have been suggested as tools for changing dietary behavior. New technologies allow users to monitor behavior remotely, potentially improving reach, adherence, and outcomes.
We conducted a systematic literature review and meta-analysis to address the following question: are remotely delivered standalone (i.e., no human contact) interventions that use SM or TF effective in changing eating behaviors?
Five databases were searched in October 2016 (updated in September 2017). Only randomized controlled trials published after 1990 were included. Trials could include any adult population with no history of disordered eating which delivered an SM or TF intervention without direct contact and recorded actual dietary consumption as an outcome. Three assessors independently screened the search results. Two reviewers extracted the study characteristics, intervention details, and outcomes, and assessed risk of bias using the Cochrane tool. Results were converted to standardized mean differences and incorporated into a 3-level (individuals and outcomes nested in studies) random effects meta-analysis.
Twenty-six studies containing 21,262 participants were identified. The majority of the studies were judged to be unclear or at high risk of bias. The meta-analysis showed dietary improvement in the intervention group compared to the control group with a standardized mean difference of 0.17 (95% CI: 0.10, 0.24; P < 0.0001). The I2 statistic for the meta-analysis was 0.77, indicating substantial heterogeneity in results. A “one study removed” sensitivity analysis showed that no single study excessively influenced the results. Standalone interventions containing self-regulatory methods have a small but significant effect on dietary behavior, and integrating these elements could be important in future interventions. However, there was substantial variation in study results that could not be explained by the characteristics we explored, and there were risk-of-bias concerns with the majority of studies.
A “Western diet” typically consists of intake high in saturated fats, salt, and sugars and low in fruit and vegetables, with most of the population in developed countries not meeting the WHO nutrient recommendations (1). This kind of poor diet is implicated in several chronic noncommunicable diseases (diabetes, some cancers, and cardiovascular disease) (2), and responsible in England for >10% of mortality and morbidity (3); hence, the development of public health initiatives targeting this area (4–6).
We used initial searches to identify keywords in PubMed to develop a strategy for adaptation to other databases (Embase, CENTRAL, PSYCHINFO, and Web of Science). The search, which was conducted in October 2016 and updated in September 2017, was restricted to those articles published after 1990 in peer-reviewed literature, in English, French, or Spanish. The protocol was placed in advance on PROSPERO: CRD42016042015 (http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42016042015) and contains the search strategies used.
As shown in Figure 1, after duplicates were removed, we retrieved 6838 articles. After abstract and paper screening, this was narrowed down to 27 articles (see Table 1) (23–49) reporting on 26 studies containing 37 interventions for inclusion, of which 23 studies (23, 24, 27–39, 41–49) were included in the meta-analysis.
Our review showed a positive but small change in diet as a result of SM or TF (based predominantly on studies of TF), although with high heterogeneity between results. That is to say, remote interventions using self-regulation methods do influence dietary change for the better and, potentially, if this effect was extrapolated over a population, it could produce a significant impact (51). This is despite potential barriers such as cost (52)—following dietary recommendations has been found to cost more and hence can become unaffordable amongst lower socioeconomic classes (53, 54)—as well as restrictions that participants face on time, motivation, social support, organizational demands, and emotional availability (55, 56).