Table 2 Data Extraction: Description of Study Characteristics in Theory Based Dietary Interventions Promoting Adherence to a Whole Dietary Pattern

Abood, D.A et al. [33] 2003

RCT

USA

Health Belief Model

53 participants in the study. N = 28 intervention, mean age 34, 96% women.

n = 25 control mean age 38, 92% women

Pre-post-test. 8 1-h weekly education session to promote knowledge and beliefs conducive to improving positive dietary practices.

INTERVENTION

1. Risk factors and prevalence rates of CVD, nutrition to reduce risk.

2. Macronutrients: food guide pyramid and sources and benefits of recommended intakes, benefits of proper nutrition, reducing barriers to increase probability of dietary changes,

3. Macronutrients; hidden sources of fat, meal and fat alternatives, benefits of fat reduction and reduction of barriers to taking such action.

4. Fruit and veg: Health protective role of fruit and veg, frequency and portion size, fibre, vitamins, benefits of increased intake of fruit and veg and barrier reduction to taking action.

5. Health benefits of weight control.

6. Benefits of eating meal regularly; distribution and preparation of low calorie-high nutrient recipes, ideas for removing barriers to healthy eating patterns.

7. Meal planning and food label reading.

8. Integration of all previous topics; HMB constructs to change nutrition behaviours to reduce risks and for behaviour maintenance; supplements, caffeine, soft drinks.

Usual care

Dietary behaviour (Whole dietary pattern)

Modified FFQ used by Boeckner and colleagues (1990)

Questionnaire on HBM.

Following the intervention, there was a significant improvement in total fat, saturated fat.

No significant effect for protein, fibre, fruit, or veg.

Manios, Y et al. [34]

2007

RCT

Greece

Health Belief Model (HBM)

Social Cognitive Theory (SCT)

82 women aged 55–65. Postmenopausal.

Intervention n = 42

Control n = 40

Mean age 60 + − 4.8 years

Every 2 weeks in a nutrition education based on HBM and SCT over 5 months.

INTERVENTION:

7 sessions based on the HBM

1. Perceived severity (What is osteoporosis)

2. Perceived susceptibility, severity, call for action (risk for osteoporosis: lifestyle choices)

3. Perceived benefits and barriers. (dietary discussion and results so far)

4. Self-efficacy, perceived barriers. Guidelines for dietary records.

5. Self-efficacy and perceived barriers. (Discussion on dietary results and changes so far)

6. Perceived benefits (Other benefits of diet)

7. Self-efficacy and perceived barriers. (Discussion of food records and barriers and benefits participants have run into)

Usual

diet

Whole diet assessed by HEI.

Grains, vegetable, fruit, milk, meat, total fat, saturated fat, cholesterol, sodium, total HEI

Healthy Eating Index (HEI)

Milk and Fat HEI scores were significantly improved. (p < 0.001). Significant decrease in grains (0.041) and total HEI (P = 0.003). Decrease in total fat was more the IG than the CG (P = 0.050) and also the increase in protein was more significant for the IG than the CG (p < 0.001)

No improvement in fruit, vegetables, saturated fat

Petrogianni, M

et al. [35] 2013

RCT

Greece

Health Belief Model and Social Cognitive Theory

108 hypercholesterolaemia adults 40–60 years.

Randomised into 2 interventions and one control.

Intervention included 7 1-h counselling and dietary lifestyle sessions held biweekly and based on HBM and SCT.

1. Perceived severity and susceptibility; cues to action (what is CVD)

2. Perceived benefits and barriers; call for action; self-monitoring; self-efficacy, (Epidemiology of CVD and ways to reduce risk factors.)

3. Perceived benefits; self-efficacy; call for action; sell-monitoring. (meal planning, setting goals)

4. Perceived benefits; self-efficacy; call for action; self-monitoring. (Guidelines for balanced diet, focus on lipids and dietary fatty acids, fasting, setting goals.

5. Perceived barriers; self-efficacy; call for action; self-monitoring. (Balanced diet plan and setting goals.

6. self-efficacy; call for action; self-monitoring. (food labels, conservatives, setting goals)

7. Progress assessment; perceived barriers and benefits. (Benefits and barriers, they have run into).

Usual diet

Dietary intake information was collected with a 3-day recall (2 consecutive weekdays and 1 weekend day)

HEI-2005 score to assess diet quality.

Significant improvement on total HEI score (P = 0.045), milk p = 0.021, dark, green vegetables and legumes p = 0.05

McPhail, M et al. [36] 2014

RCT

Australia

Health Action Process Approach. (HAPA)

87 participants attending primary care diabetes clinic with a diagnosis of T2D.

4-month intervention consisting of self-guided HAPA based workbooks in addition to 2 telephone calls to assist participants with program implementation.

Treatment as usual

Whole diet consisting of, fruit, veg, grain, meat, dairy, beverages, sodium, saturated fat and alcohol.

Diet Guidelines Index (DGI).

HAPA questionnaire.

Healthy eating was not associated with HAPA variables nor did they predict healthy eating after intervention.

Miller, C.K et al. [37] 2016

RCT

USA

Health Action Process Approach. (HAPA)

68 participants aged 18–65 years. Mean age 51. 14 males, 54 females.

16-week lifestyle intervention based on the HAPA. 60-min weekly lifestyle coaching sessions.

• The first 8 sessions presented the intervention goals, taught information about modifying energy intake and expenditure and helped participants self-monitor.

• The following 8 sessions focussed on problem solving to achieving lifestyle goals, preventing relapse, motivating sustained behavioural change.

• Action plans introduced at week 9 and later review of the success of action plan.

Control group received a booklet on lifestyle changes for diabetes prevention.

Whole diet assessed by the AHEI.

Alternative Healthy Eating Index, 2010. (AHEI)

HAPA questionnaire

There was a significant increase in total AHEI score and in consumption of fruit and a significant decrease in red and processed meat, trans fat and sodium (p < .01).

Rodriguez, M.A et al. [38] 2019

RCT

USA

(TTM)

Stage of change

533 adults with uncontrolled hypertension

Tailored Intervention: TTM based MONTHLY telephone counselling for 6 months tailored to stage of change.

• Pre-contemplation/contemplation stage: Information and feedback about achieving DASH diet, imagery exercise designed to release emotions related to DASH diet, self/environmental evaluation (goals, values, consequences of non-adherence).

• Preparation stage: Promoting autonomy and self-efficacy towards DASH diet by thinking about past successes in behaviour change

• Action stage: Counterconditioning; substituting unhealthy foods for healthy foods, rewarding engagement with DASH diet, introducing prompts/cues for DASH adherence

• Maintenance: Similar to Action stage with a focus on relapse prevention.

• Decisional balance: Pros and cons of DASH diet. Each con was addressed through problem solving and each pro was further explored.

NON-Tailored intervention:

Monthly calls to address hypertension management with general information on diet, exercise, medication, sun safety, sleep hygiene, vision/hearing problems

Usual care

DASH diet

Improve adherence to DASH diet

TTM stage

Significant improvement in overall DASH score.

No improvement in individual food groups

Tailored intervention effectively advanced participants stage of change

Peters, N.C et al. [39] 2014

RCT

USA

SCT

71 healthy post-menopausal women aged between 50 and 72

One-year Intervention: Three eating patterns

Whole food plan, The Food Power eating plan, The Flax Plus eating plan.

Behaviour Intervention:

• The first 14 weeks (adoption stage) each group met weekly with behavioural classes alternating with cooking classes, to motivate participants to eat according to their eating plan.

• The following 2 months (maintenance stage) included bi-weekly behavioural sessions including food demonstrations and tastings.

• The final 6 months (maintenance stage) involved monthly sessions reviewing progress, goal setting and action planning.

N/A

Whole dietary pattern

My Pyramid

Adherence to eating pattern with monthly 24 h recall

Psycho-social questionnaire

There were no changes in psychosocial factors overtime.

In the whole food eating pattern, significant improvements were found in the food group, beans and meat, poultry, eggs.

In the moderate fat group, significant improvements were found for fruit, vegetables, sugar.

LeBlanc, V et al. [40] 2015

Non-RCT

Canada

Self-determination theory

(SDT)

64 men and 59 premenopausal women aged between 25 and 50.

Non-random intervention study.

12-week nutritional program based on STD and uses a MI approach.

INTERVENTION

3 GROUP SESSIONS

3 INDIVIDUAL SESSIONS AND 4 FOLLOW UP PHONE CALLS.

3 GROUP SESSIONS.

LECTURE; EXPLAINING PRINCIPLES OF MED DIET

• 3HR Med diet cooking lesson

• 3-h Mediterranean potluck dinner aimed at discussing barriers met in adopting dietary recommendations since the beginning.

3 individual sessions and follow up calls.

• These assessed dietary changes and to determine progressive goals with the potential and realistic strategies aimed at improving the adherence to Med Diet principles. In accordance with the SDT, basic psychological needs were supported during the intervention (autonomy, competence, and relatedness)

No control

Mediterranean diet

Med score calculated based on validate FFQ

The regulation of eating scale

Changes in eating-related self-determined motivation was positively associated with changes in Med score at follow up in men only.

Schwarzer, R et al. [41] 2017

Non-RCT

Italy

Spain

Greece

HAPA

112 participants.

47 men

65 women

Mean age 42 range 18–65 years.

Pilot intervention study. Single arm online intervention.

The online platform delivered a lifestyle intervention that implemented theory-based behaviour change components based on the HAPA.

INTERVENTION

It is unclear how long the intervention was, this author used intervention mapping of behaviour change techniques to theoretical constructs.

The intervention had 5 sections on Med diet and eating healthily.

• Risk perception; Outcome expectancy; Self-efficacy; Planning; Action control

No control

Mediterranean Diet Adherence Screener (MEDAS)

Measures:

•Dietary behaviours index

•Psychological constructs

1.Positive diet-specific outcome expectancy

2.Diet specific planning

3.Diet specific action control

4.Stages of change.

The intervention showed overall improvements in Med diet adherence.