None listed
Conditions
Brief summary
Several studies have now reported that modest improvements in diet (eating more fruit and vegetables) can lead to improvements in mood (Firth et al., 2019; Jacka et al., 2017; Parletta et al., 2019). In our recent study, Francis et al., (2019) demonstrated that a 3-week diet intervention for participants who reported low mood experienced significant improvement after the intervention, compared to controls. The usual explanation for these effects of diet is ‘physiological’. However, an alternative explanation is that positive expectations about a treatment (i.e., a placebo effect) and ‘taking control’ of events in your life (called self-efficacy) can both make you feel better. It is very likely that people believe that fresh food is good for you. It is also very likely that taking charge of ones’ diet is likely to increase feelings of self-efficacy. Together, these psychological effects could improve a person’s mood. Therefore, the aim of our study is to investigate if the beneficial effects of a healthy diet on mood are in part from positive expectations and improved self-efficacy.
Interventions
Participants will be randomly allocated to one of four conditions: 1) fresh food condition, 2) canned and frozen food condition, 3) cooking condition, and 4) waitlist condition (see comparator/control treatment field below for more details).
Those in the fresh food condition will be instructed to increase intake of fish, fruits, vegetables, nuts, seeds, natural diary and wholegrain cereals, and decrease refined carbohydrate, sugar, fatty or processed meats and soft-drinks. Recommendations are
Participants will be randomly allocated to one of four conditions: 1) fresh food condition, 2) canned and frozen food condition, 3) cooking condition, and 4) waitlist condition (see comparator/control treatment field below for more details). Those in the fresh food condition will be instructed to increase intake of fish, fruits, vegetables, nuts, seeds, natural diary and wholegrain cereals, and decrease refined carbohydrate, sugar, fatty or processed meats and soft-drinks. Recommendations are based on the Australian Guide to Healthy Eating, as well as Mediterranean diet principles known to be associated with improved mood, incorporate BeyondBlue behavioural tips for eating well, designed by a registered dietician and administered via video (approximately 10 - 20mins in length). The video provides information on the 5 major food groups in the Australian Guide to Healthy Eating (wholegrains, protein, dairy, fruit, vegetables), as well as recommendations to additionally consume specific foods known for their health benefits (olive oil, avocados, nuts and seeds, and spices). Participants will be provided a sample meal plan, shopping list and recipes, based on the Australian Guide to Healthy Eating. Participants will be provided online access to the diet intervention video and FAQs plus a questions facility on an online learning platform, monitored by the research team (incl. a registered psychologist). All diets will be ad libitum with no adherence to calorie restriction using the ingredients and reception provided. Participants allocated to the canned and frozen food condition will be instructed to follow the same dietary changes as described in the fresh food condition above, however, they will be encouraged to consume a Mediterranean diet mainly via canned and frozen equivalents. They will be provided with the same sample meal plan and recipes as the fresh food condition, however adjusted to include canned and frozen ingredients alternatives. Participants will be provided online access to the diet intervention video and FAQs plus a questions facility on an online learning platform, monitored by the research team (incl. a registered psychologist), again with content adjusted to include canned and frozen ingredients. Participants will be asked to complete a diet diary once a week during the study to check for diet compliance. In lieu of encouraging a Mediterranean based diet change, those in the cooking condition will be encouraged to continue consuming the same food they already typically eat, while being required to prepare and cook it for themselves, as opposed to purchasing takeout or pre-made packet items. For example, participants will be encouraged to shop for ingredients, prepare and cook their main meals such as pizza, toasties, burgers, chicken wings, and macaroni and cheese; as well as desserts including cookies, brownies, pastries and cakes, and snacks including milk shakes, scrolls, salted popcorn. They will be instructed to do this via the same resources (sample meal plans, recipes and online access to a learning platform) with the content adjusted accordingly. The cooking condition will also be required to complete a diet diary once a week. On day 21 the cooking group will be offered the resources used by the fresh food group. All participants in the active conditions will be provided online access to the diet intervention video and answers to frequently asked questions. The intervention will last 3-weeks, and they will receive a telephone call mid intervention (approximately 5 minutes in length to answer any questions regarding the diet and check for diet adherence), as well as weekly text messages with a brief survey about their diet intake for the preceding day. To monitor diet adherence, all participants will be asked to submit grocery receipts (upon which they will receive a $60.00 grocery voucher to reimburse the cost of foods), complete a weekly diet diary, and have their skin carotenoid levels tested (via a spectrophotometer) before and after the study (contact will be reduced depending on general health recommendations during the global pandemic).
Sponsors
Macquarie University
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
17 Years to 35 Years
Healthy volunteers
No
Inclusion criteria
Elevated (>7) scores on the Depression, Anxiety and Stress Scale-21 Depression subscale (DASS-21-D); Score > 57 on the Dietary Fat and Sugar Screener (DFS); and score amongst the lowest quartile range for the Positive and Negative Affect Scale (PANAS - GEN).
Exclusion criteria
Not pregnant, dieting, no history of eating disorders or metabolic disease(s), no history of psychological illness other than depression or anxiety, not experienced two or more failed trials of antidepressant, not reported medical condition that could be adversely affected by diet change, no known or suspected clinically unstable systemic medical disorder or gut based medical disorders i.,e Crohn's disease, no poor proficiency in English, no recent self-reported illicit drug or alcohol use, no sickness in the past week, and no food allergies. If a participant is receiving antidepressant medication or therapy, they need to be on the same treatment for at least 2 weeks before participation.
Outcome results
None listed