A scoping review of multiple studies reveals various strategies that can potentially reduce the intake of discretionary (junk) food in adults and children
Nowadays, it is difficult to avoid eating junk food, considering that it is widely accessible and is the subject of highly attractive marketing schemes. It is almost common knowledge that addictions to junk food can lead to obesity and increase your risk of developing health complications. These “discretionary choices” include foods and beverages that are high in saturated fat and added sugars or salt. They are the typical fast foods, sugary snacks and beverages that are not required for a healthy diet, but frequently displace more nutritional foods. Given the urgency of weight loss and maintenance in the midst of the ongoing obesity epidemic, thorough investigations have to be performed in order to provide useful information to the public.
As published in the International Journal of Behavioral Nutrition and Physical Activity, researchers have conducted a scoping review to determine dietary intervention strategies that may be capable of decreasing the intake of discretionary foods in children and adults. A scoping review is commonly used to map out existing literature on a certain research topic, and is comprised of several key phases:
- Identifying the research question of interest
- Identifying studies relevant to the question
- Selecting which studies to be reviewed
- Mapping information and data included in relevant studies
- Analyzing, summarizing, and reporting results of the review
The team of researchers searched through electronic databases including Cochrane Library, Ovid, EbscoHost, and Scopus to find and filter publications of relevant studies in English and released up to July 20th, 2015. The final 44 included studies involved healthy participants aged from 2 to 65 years old, and were either randomized controlled trials (RCT) or comparator group studies that focused on interventions to reduce discretionary food consumption. These studies encompassed a vast range of strategies, including:
- Reformulation (changing diet of higher saturated fat to lower saturated fat)
- Substitution (replacing normal snacks with high fibre snacks, replacing biscuits with fruit)
- Restriction or elimination (reducing the portion of meal components, increasing amount of low-density food)
- Supplementation (adding certain foods and beverages to the diet)
- Education on nutrition (providing permissive and restrictive messages for a defined period)
- Incorporation of inexpensive, healthy foods in the workplace
Both chronic and acute studies involving the mentioned strategies were examined. Chronic studies were those that required participants to intake a food or beverage daily for duration of weeks, with the intake measured after the intervention was complete. In contrast, acute studies demanded participants to consume a food or beverage only once, or once a week over a few weeks, with calories measured after their intake.
Through this scoping review, the extensive findings have shown that there is no single strategy that can unquestionably decrease the quantity of discretionary choices in adults and/or children. Reformulation of fat can be used to reduce saturated fat consumption, but its effects on weight and energy intake are still unclear. Certain research demonstrated that lower density (or more aerated) food resulted in less energy consumed, and that adopting a lower density meal (e.g. salads) had reduced the amount of energy intake for that meal. Hence, controlling food density may be able to reduce discretionary choices.
Substitution strategies yielded mixed results. Chronic studies that substituted high fibre snacks, almonds or cereal bars for common snacks had no impact on micronutrient intake or bodyweight in adults. However, substitution of high fibre snacks in children had resulted in increased ingestion of total grains and sweets. Nonetheless, the effects of substituting high fibre snacks, fruits, as well as low or no-caloric drinks for discretionary choices may be favorable.
The restriction or elimination strategy was determined to be mostly beneficial for decreasing short-term energy intake. This involved either decreasing portion sizes of a meal component or increasing the portion of a low-density meal. It was reasoned that lower-energy-density foods may be able to replace higher-energy-density foods at a meal or discretionary choices.
Supplementing diets with nuts and wholegrain cereals instead of discretionary choices resulted in an improved diet quality. On the other hand, the health benefits of including high-sugar ready-to-eat cereal (RTEC) are more ambiguous, since they generally contain large quantities of added sugar and salt. It was also shown that water and fruit intake can have positive effects towards reducing discretionary choices.
Moreover, educational strategies which used both permissive and restrictive messages with regards to the consumption of junk food may be able to alter the behaviour of certain age groups. Simple messages promoting drinking water instead of artificially sweetened beverages had produced a significant reduction in carbonated beverage intake among those aged 9-12 years old, but did not result in weight loss or BMI reduction. As well, young adults who read cautionary messages about junk food had consumed a lesser amount of high calorie snacks. For adults, offering inexpensive or free nutritious food in the workplace improved the quality of their diet.
Through this comprehensive review, it is evident that there are a wide variety of strategies that can be applied to reduce the intake of discretionary choices. However, further investigations need to be done in order to develop practical interventions and observe effects on a much larger scale.
Written By: Michelle Tu, BSc