Table 1.
Study characteristics.
| Author, Date | Country | Participants | Dietary Intervention | Behavioural Support | Weight Loss in Primary Intervention | Data Collection | Data Analysis |
|---|---|---|---|---|---|---|---|
| Studies focusing on weight loss | |||||||
| Abel et al., 2018 [36] | New Zealand | Adults with newly diagnosed prediabetes (n = 20) | 6 months of education on healthy eating principles with no specific calorie reduction advice. | 3 times over 6 months plus 6 weekly group education sessions. | At 6 months: Intervention −1.3 kg, Control +0.8 kg (difference p < 0.001). | Semi-structured interviews | Thematic analysis |
| Fazzino et al., 2016 [37] | United States of America | Rural breast cancer survivors (n = 186) | 6 months of 2 meal replacement shakes and at least 5 fruits of vegetables per day, plus 225 min of physical activity per week | Six months of weekly one-hour group teleconference calls | At 6 months: −12.8± 6.8% (p-value NA) | Semi-structured interviews | Thematic analysis |
| Haigh et al. 2019 [38] | England | Adults with non-alcoholic fatty liver disease (n = 19) | 12 weeks of the Mediterranean diet, with no specific calorie reduction advice. | Single session of nutrition counselling and education at baseline. | At 12 weeks: 99.2 ± 17.0 kg at baseline to 96.8 ± 17.5 kg (p = 0.001) | Semi-structured interviews | Thematic analysis |
| Hammarström et al., 2014 [39] | Sweden | Post-menopausal females (n = 12) | 2-year RCT of Paleolithic diet or normal Nordic recommendations, with no specific calorie reduction advice. | 8 group sessions in first 6 months, plus 4 sessions across 18 months. | At 24 months: −6.2 kg in Paleolithic diet vs. −3.7 kg Normal Nordic recommendations (p = NS) | Semi-structured interviews | Thematic analysis |
| McParlin et al., 2018 [40] | England | Females with gestational diabetes mellitus (n = 12) | 4 weeks of 1200 kcal/day | Hour-long consultation at baseline and weekly reviews | At 4 weeks: −1.6 ± 1.7 kg. Mean weight change was −0.4 kg/week in the study group vs. +0.3 kg/week in the control group (p = 0.002) | Semi-structured interviews | Theoretical Domains Framework |
| Rehackova et al., 2017 [41] | England | Overweight adults (n = 15) | 8 weeks of 800 kcal diet using meal replacements | Weekly individual support | At 8−weeks: −14.2 kg (98.0 ± 2.6 to 83.8 ± 2.4 kg, p < 0.001) | Semi-structured interviews | Thematic analysis |
| Studies focusing on weight loss and weight loss maintenance | |||||||
| Bertz et al., 2015 [42] | Sweden | Postpartum females (n = 21) | 12-week RCT of calorie-reduced diet (by 500 kcal/day), exercise (45 min brisk walk 4 times per week), diet and exercise, or control. | At baseline and at 6 weeks, plus fortnightly text messages | At 12 weeks: Diet −9.7 ± 4.8% (p < 0.001), Diet + Exercise (p < 0.001). | Semi-structured interviews | Grounded theory |
| Brandt et al., 2018 [43] | Denmark | Overweight patients (n = 10) | 20-month online e-health tool with no specific calorie reduction advice. | 4 months of weekly reviews, plus 16 months of optional input | At 4 months: −7.0 kg (p < 0.001). | Semi-structured interviews | Thematic analysis |
| Kleine et al. 2019 [44] | United States of America | Overweight adults (n = 61) | 8–12 weeks of a proprietary meal replacement programme | 20 sessions over 1 year | NA | Focus groups | Content analysis theory |
| Lawford et al. 2021 [45] | Australia | Adults with osteoarthritis (n = 24) | 6-month RCT of exercise, exercise plus 800 kcal diet with meal replacements, or control | 6 months of monthly virtual consults and access to online resources | NA | Semi-structured interviews | Grounded theory |
| Metzgar et al., 2015 [46] | United States of America | Overweight and obese females (n = 23) | 18-week RCT of calorie-reduced diet (by 500 kcal per day) plus energy-controlled chocolate snacks or no chocolate snacks. | 18 weeks of weekly group education session | At 18 weeks: −4.4 ± 0.6 kg (p < 0.001) in dark chocolate group; −5.0 ± 0.9 kg (p < 0.001) in non-chocolate group | Focus groups | Thematic analysis |
| Östberg et al., 2011 [47] | Sweden | Overweight adults (n = 19) | 12 weeks of 800 kcal diet using meal replacements, plus 9 months of corset treatment for successful participants. | 6 group sessions for 12 week phase, 6 sessions during corset treatment. | 85% lost at least 8kg (p-value NA) | Focus groups | Grounded theory |
| Terranova et al., 2017 [48] | Australia | Breast cancer survivors (n = 14) | 6 months of calorie-reduced diet (by 500 kcal per day) and 210 min of physical activity per week | 6 weekly calls, 10 fortnightly calls, and 6 months of tailored text messages | At 6 months: −5.5 kg (p < 0.05) |
Semi-structured interviews | Thematic analysis |
| Wycherley et al., 2011 [49] | Australia | Adults with type 2 diabetes (n = 30) | 16-week RCT of reduced-calorie diet with or without supervised resistance training 3 days per week | Fortnightly individual reviews | At 16 weeks: −8.7% to −12.7% across all interventions (p < 0.001) | Semi-structured interviews | Thematic analysis |
Abbreviations: RCT = randomised controlled trial, NA = not available.