Table 1.
Characteristics of randomised controlled trials
| Trial | n | Dropout (%) | Follow-up (months) | Comorbidities and drugs | Mean age (SD) | Female (%) | Smoke (%) | Ethnicity | Mean BMI, kg/m2 (SD) | Main weight loss interventions | Comparisons |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Abbenhardt, 2013, USA26 27 | 439 | 9.1 | 12 | NR | 58.0 (5.0) | 100 | 0 | White | 30.9 (4.0) | Group 1—Diet based on DPP and Look AHEAD (1200-2000 kcal/d, <30% calories from fat, <10% from saturated fat, for 10% weight loss) Group 2—Diet as above plus exercise programme |
Group 3—Control Group 4—Exercise programme |
| Abed, 2013, Australia28 | 150 | 46.0 | 15 | Atrial fibrillation | 60.1 (9.9) | 33 | 5 | White | 33.3 (3.8) | Group 1—Diet (800-1200 kcal/d for 8 weeks as 2 VLCD sachets and 1 low GI meal; weight maintenance low GI and low fat diet) and exercise advice |
Group 2—Control |
| Ackerman, 2015, USA29 | 509 | 15.5 | 12 | Impaired glucose tolerance or impaired fasting glucose | 51.0 (12.1) | 70.7 | NR | Mixed | 36.8 (8.5) | Group 1—Diet based on DPP (low calorie, <25% calories from fat, low saturated fat, for 5-7% weight loss) and exercise advice | Group 2—Control |
| Andrews, 2011, UK30 | 593 | 2.4 | 12 | Type 2 diabetes | 60.0 (10.1) | 35 | 8 | White | 31.7 (5.7) | Group 1—Diet based on Diabetes UK and Food Standards Agency (<35% calories from fat, <10% from saturated fat, low GI, for 5-10% weight loss) Group 2—Diet as above and exercise advice |
Group 3—Control |
| Appel, 2003, USA (PREMIER)31-33 | 810 | 11.4 | 18 | Above normal blood pressure | 50.3 (8.9) | 62 | 5 | Mixed | 33.1 (5.8) | Group 1—Diet (≤30% calories from fat, ≤10% from saturated fat, ≥6.8 kg weight loss) and exercise programme Group 2—Diet based on DASH (≤25% calories from fat, ≤7% from saturated fat, ≥6.8 kg weight loss) and exercise programme |
Group 3—Control |
| Ard, 2016, USA34 | 167 | 11.4 | 12 | Drugs for diabetes, lipids, or blood pressure | 70.3 (4.7) | 62.2 | NR | Mixed | 33.7 (2.95) | Group 1—Diet (28% calories from fat and 500 kcal/d deficit) and exercise programme Group 2—Diet (28% fat for weight maintenance) and exercise programme |
Group 3—Exercise programme |
| Aveyard, 2016, UK35 | 1882 | 24.6 | 12 | NR | 56.0 (16.1) | 57.2 | NR | White | 34.9 (4.8) | Group 1—Diet mainly Slimming World (low fat and low saturated fat) and exercise advice | Group 2—Control |
| Bennett, 2012, USA36 | 365 | 14.0 | 24 | Drugs for blood pressure | 54.6 (10.9) | 69 | 18 | Mixed | 37.0 (5.1) | Group 1—Diet (low fat and low saturated fat, weight reducing diet) and exercise advice | Group 2—Control |
| Anderson, 2014, UK (BeWEL)37 | 329 | 7.3 | 12 | Colorectal adenoma removal | 63.6 (6.8) | 26 | NR | White | 30.7 (4.2) | Group 1—Diet based on British Heart Foundation (600 kcal/d deficit, low fat, low saturated fat, for 7% weight loss) and exercise advice | Group 2—Control |
| Bhopal, 2014, UK16 | 171 | 2.3 | 36 | Impaired glucose tolerance or impaired fasting glucose | 52.5 (10.3) | 54 | 6 | Asian | 30.6 (4.8) | Group 1—Diet based on the Counterweight programme (500-600 kcal/d deficit, 30% calories from fat, for 5-10% weight loss) and exercise advice | Group 2—Control |
| Blonk, 1994, Netherlands38 | 60 | 11.7 | 24 | Type 2 diabetes | 58.8* | 57 | NR | White | 32.0* | Group 1—Diet (500 kcal/d deficit, 30% calories from fat, low saturated fat) and exercise programme | Group 2—Control |
| Burke, 2008, Australia39 | 241 | 41.9 | 40 | Drugs for blood pressure | 56.2 (7.4) | 56 | 3 | White | 30.1 (2.7) | Group 1—Diet based on DASH (<30% calories from fat, low sat fat, for 5-10% weight loss) and exercise advice | Group 2—Control |
| Daumit, 2013, USA40 | 291 | 4.1 | 18 | Psychiatric illness rehabilitation | 45.3 (11.3) | 50 | NR | Mixed | 36.3 (7.3) | Group 1—Diet based on DASH (low fat, low saturated fat, for 4.5 kg weight loss) and exercise programme | Group 2—Control |
| Davis, 1993, USA (TAIM)41 | 587 | 31.0 | 30 | Mild hypertension | 47.9 (NR) | 46 | 16 | Mixed | 30.2 (NR) | Group 1—Diet (low fat, for 4.5kg or 10% weight loss) and exercise advice | Group 2—Control |
| de Vos, 2014, Netherlands42-44 | 407 | 39.3 | 80 | Free of knee osteoarthritis or rheumatic diseases | 55.7 (3.2) | 100 | 17.9 | White | 32.4 (4.3) | Group 1—Diet (tailored low fat or low calorie reducing diet) and exercise programme | Group 2—Control |
| de Waard, 1993, Netherlands, Poland45 | 107 | 28.6 | 36 Netherlands, 12 Poland | Breast cancer | 50-69† | 100 | NR | White | 30.2 (NR) | Group 1—Diet (1000-1500 kcal/d balanced diet) | Group 2—Control |
| DPP, 2002, USA4 46 47 | 3234 | 9.9 | 34 | Impaired glucose tolerance | 50.6 (10.7) | 67 | 7 | Mixed | 34.0 (6.7) | Group 1—Diet (low calorie, <25% calories from fat, low saturated fat, for 7% weight loss) and exercise programme | Group 2—Control and metformin placebo |
| Finnish DPS, 2009, Finland3 48 49 | 523 | 16.4 | 138 | Impaired glucose tolerance | 55.2 (7.2) | 67 | 7 | White | 31.3 (4.5) | Group 1—Diet (<30% calories from fat, <10% from saturated fat, for ≥5% weight loss) and exercise programme | Group 2—Control |
| Fitzgibbon, 2010, USA50 | 213 | 10.8 | 18 | NR | 46.0 (8.4) | 100 | NR | Black | 39.2 (5.7) | Group 1—Diet (low calorie, low fat, for 7% weight loss) and exercise programme | Group 2—Control |
| Gabriel, 2011, USA51 | 508 | 10.2 | 48 | Postmenopausal, some on hormone replacement therapy | 57.0 (2.9) | 100 | 6 | White | 30.8 (3.8) | Group 1—Diet (<17% calories from fat, <4% from saturated fat, 1300-1500 kcal/d) and exercise advice | Group 2—Control |
| Goodwin, 2014, Canada, USA52 | 338 | 12.7 | 24 | Breast cancer, letrozole therapy | 61.0 (7.2) | 100 | 7 | White | 31.3 (5.2) | Group 1—Diet based on DPP (20% calories from fat, 500-1000 kcal/d deficit) and exercise advice | Group 2—Control |
| Greaves, 2015, UK53 | 108 | 11.1 | 12 | High cardiovascular risk | 65.1 (7.0) | 30.6 | NR | White | 32.7 (3.1) | Group 1—Diet (low fat, low sat fat diet, for ≥5% weight loss) and exercise advice | Group 2—Control |
| Green, 2015, USA54 | 200 | 18.0 | 24 | Antipsychotic drugs | 47.2 (10.6) | 72 | 33 | White | 38.3 (8.3) | Group 1—Diet based on DASH (≤30% calories from fat, ≤10% from saturated fat, for 4.5-6.8 kg weight loss) and exercise programme | Group 2—Control |
| Heller, 1988, UK55 | 87 | 13.8 | 12 | Diabetes | 56.5 (7.7) | 52 | NR | White | 31.6 (3.3) | Group 1—Diet (low sugar, high fibre for weight loss) | Group 2—Control |
| Heshka, 2003, USA56 | 423 | 27.0 | 24 | NR | 44.5 (10.0) | 85 | 9 | White | 33.7 (3.6) | Group 1—Diet (Weight Watchers for weight loss of 0.9 kg/w) and exercise advice | Group 2—Control |
| Horie, 2016, Brazil57 | 80 | 6.3 | 12 | Mild cognitive impairment | 68.1 (4.9) | 83.8 | 1.3 | Mixed | 35.5 (4.4) | Group 1—Diet (<30% calories from fat, 500 kcal/d deficit) and exercise advice | Group 2—Control |
| Hunt, 2014, UK (FFIT)58 | 748 | 17.7 | 12 | NR | 47.1 (8.0) | 0 | NR | White | 35.3 (4.9) | Group 1—Diet (low fat, 600 kcal/d deficit, healthy eating) and exercise programme | Group 2—Control |
| Hydrie, 2012, Pakistan59 | 317 | 13.6 | 18 | Impaired glucose tolerance | 43.6 (9.9) | 25 | NR | Asian | 27.0 (5.0) | Group 1—Diet (<30% calories from fat, for ≥5% weight loss) and exercise programme | Group 2—Control |
| Katula, 2013, USA60 | 301 | 13.3 | 24 | Impaired fasting glucose | 57.9 (9.5) | 58 | 5 | Mixed | 32.7 (4.0) | Group 1—Diet based on DPP (low calorie, 25-30% fat, 7% saturated fat, 1200-1800 kcal/d, for 5-7% weight loss) and exercise advice | Group 2—Control |
| Li Da Qing, 2014, China17 61-63 | 577 (33 clinics) | 8.1 | 72 | Impaired glucose tolerance | 45.0 (9.1) | 47 | 41 | Asian | 25.8 (3.8) | Group 1—Diet (BMI <25, 25-30 kcal/kg, 25-30% calories from fat; BMI ≥25 reduce calories to lose 0.5-1 kg/month, until BMI=23). Group 2—Diet as above and exercise advice |
Group 3—Control Group 4—Exercise advice |
| Logue, 2005, USA64 | 665 | 34.6 | 24 | NR | 52.3 (NR) | 69 | NR | Mixed | 34.2 (NR) | Group 1—Diet based on DGA (low calorie, low fat, low saturated fat, portion control) and exercise advice | Group 2—Control |
| Look AHEAD, 2013, USA65 66 | 5145 | 3.7 | 115 | Type 2 diabetes | 58.8 (6.9) | 60 | 4 | Mixed | 36.0 (5.9) | Group 1—Diet (1200-1800 kcal/d, <30% calories from fat, <10% from saturated fat, for 7% weight loss, meal replacements) and exercise programme | Group 2—Control |
| Ma, 2013, USA67 | 241 | 34.4 | 24 | Impaired fasting glucose or metabolic syndrome | 52.9 (10.6) | 47 | NR | White | 32.0 (5.4) | Group 1—Diet based on DPP (500-1000 kcal/d deficit, 25% calories from fat, for 7% weight loss) and exercise programme Group 2—Self directed diet and exercise as above |
Group 3—Control |
| Mengham, 1999, UK68 | 75 | 1.3 | 12 | Diabetes | 60.6 (12.5) | 45 | NR | White | 31.6 (4.6) | Group 1—Diet based on British Dietetic Association recommendations (low fat) | Group 2—Control |
| Messier, 2013, USA69 | 454 | 12.1 | 18 | Knee osteoarthritis | 66 (NR)6 | 72 | NR | White | 33.6 (3.7) | Group 1—Diet based on DGA (800-1000 kcal/d deficit, meal replacements ≤2/day, <30% calories from fat) Group 2—Diet as above and exercise programme |
Group 3—Exercise programme |
| Oldroyd, 2006, UK70 | 78 | 30.8 | 24 | Impaired glucose tolerance | 57.9 (NR) | 44 | NR | White | 30.2 (5.3) | Group 1—Diet (aim for BMI <25, ≤30% calories from fat, PUFA/SFA ratio ≥1.0) and exercise programme | Group 2—Control |
| O’Neil, 2016, USA71 | 563 | 14.0 | 12 | Type 2 diabetes | 55.1 (19.1) | 71.0 | NR | Mixed | 37.1 (5.7) | Group 1—Diet (Weight Watchers, hypoenergetic healthy eating) and exercise advice | Group 2—Control |
| Patrick, 2011, USA72 | 441 | 29.9 | 12 | NR | 43.9 (8.0) | 0 | NR | White | 34.3 (4.1) | Group 1—Diet based on DGA (saturated fat ≤20 g/day) and exercise advice | Group 2—Control |
| Penn, 2009, UK73 | 102 | 48.0 | 37 | Impaired glucose tolerance | 57.1 (NR) | 60 | NR | White | 33.8 (5.1) | Group 1—Diet (reduced saturated fat and <30% calories from fat until BMI <25) and exercise advice | Group 2—Control |
| Perri, 2014, USA74 | 612 | 19.6 | 24 | NR | 52.3 (11.5) | 78 | NR | White | 36.3 (4.0) | Groups 1-3—Diet based on DPP (1200-1800 kcal/d, low fat) and exercise advice. Three groups received different intensities of both diet and exercise interventions | Group 4—Control |
| Ramachandran, 2006, India75 | 531 | 5.5 | 30 | Impaired glucose tolerance | 45.9 (5.7) | 21 | 22 | Asian | 25.8 (3.5) | Group 1—Diet (low calorie, low fat) and exercise advice Group 2—Diet as above and exercise advice and metformin |
Group 3—Control Group 4—Metformin |
| Rejeski, 2011, USA (CLIP)76 | 288 | 13.5 | 18 | Recent cardiovascular disease, metabolic syndrome, or mobility limitation | 67.1 (4.8) | 67 | NR | White | 32.8 (3.8) | Group 1—Diet based on DGA (1200-1800 kcal/d, low fat, for 7-10% weight loss) and exercise programme | Group 2—Control Group 3—Exercise programme |
| Rock, 2015, USA77 78 | 698 | 15.9 | 24 | Breast cancer | 56 (NR)9 | 100 | 3.45 | White | 31.5 (4.7) | Group 1—Diet (500-1000 kcal/d deficit, low energy density, for 7% weight loss) and exercise advice | Group 2—Control |
| Ross, 2012, Canada (PROACTIVE)79 | 490 | 19.2 | 24 | NR | 51.8 (11.4) | 70 | NR | White | 32.3 (4.2) | Group 1—Diet (balanced Mediterranean type diet for weight loss, 5-10% reduction in waist circumference) and exercise advice | Group 2—Control |
| Saito, 2011, Japan80 | 641 | 9.2 | 36 | Impaired fasting glucose | 49.0* | 29 | 27 | Asian | 27.0 (2.6) | Group 1—Diet (low calorie, 20-25% calories from fat, for 5% weight loss) and exercise advice | Group 2—Control |
| Shea, 2010, USA (ADAPT)81 82 | 318 | 20.8 | 96 | Knee osteoarthritis | 68.7 (5.4) | 72 | NR | Mixed | 34.2 (5.5) | Group 1—Diet based on TONE based (500 kcal/d deficit, fat and portion control, for 5% weight loss) Group 2—Diet as above and exercise programme |
Group 3—Control Group 4—Exercise programme |
| Shea, 2011, USA (TONE) 83-85 | 585 | <20 | 152 | Drugs for blood pressure | 66.0 (4.3) | 53 | 5 | Mixed | 31.2 (2.3) | Group 1—Diet (low calorie, low fat, for ≥4.5 kg weight loss) and exercise programme Group 2—Diet (low calorie, low fat, for ≥4.5 kg weight loss), exercise programme, and sodium restriction |
Group 3—Control Group 4—Sodium restriction |
| TOHP II, 2007, USA86 87 | 2382 | 23.0 | 144 | High normal diastolic blood pressure | 43.6 (6.1) | 34 | 9 | Mixed | 30.9 (3.1) | Group 1—Diet (low calorie, low fat, for ≥4.5 kg weight loss) and exercise programme Group 2—Diet (low calorie, low fat, for ≥4.5 kg weight loss), exercise programme, for sodium restriction |
Group 3—Control Group 4—Sodium restriction |
| Toobert, 2000, USA88 | 28 | 10.7 | 24 | Coronary heart disease | 63.6 (10.4) | 100 | 7 | White | 32.0 (4.8) | Group 1—Diet based on Ornish (vegetarian diet, <10% calories from fat) and exercise programme | Group 2—Control |
| Uusitupa, 1993, Finland89-91 | 90 | 8.9 | 24 | Type 2 diabetes | 53.2 (6.6) | 43 | 17 | White | 33.5 (5.1) | Group 1—Diet (≤30% calories from fat, ≤10% from saturated fat) and exercise advice | Group 2—Control |
| Villareal, 2011, USA92 | 107 | 13.1 | 12 | Frailty | 69.7 (4.0) | 63 | NR | White | 37.2 (5.0) | Group 1—Diet (balanced diet, 500-750 kcal/d deficit, for 10% weight loss) Group 2—Diet as above and exercise programme |
Group 3—Control Group 4—Exercise programme |
| Wadden, 2011, USA93 | 390 | 13.8 | 24 | Metabolic syndrome | 51.5 (11.5) | 80 | NR | Mixed | 38.5 (4.7) | Group 1—Diet based on DPP (1200-1800 kcal/d, 20-35% calories from fat) and exercise advice (brief counselling) Group 2—Diet based on DPP (1200-1800 kcal/d, 20-35% calories from fat; meal replacements, orlistat or sibutramine if required) and exercise advice (enhanced counselling) |
Group 3—Control |
| Wing, 2010, USA (PRIDE) 94 95 | 338 | 14.5 | 18 | Urinary incontinence | 52.7 (10.3) | 100 | 5 | Mixed | 36.3 (5.3) | Group 1—Diet based on DPP and Look AHEAD (1200-1800 kcal/d, <30% calories from fat, for 7-9% weight loss, SlimFast vouchers) and exercise advice | Group 2—Control |
| Yardley, 2014, UK96 | 179 | 31.3 | 12 | NR | 51.2 (13.1) | 64 | NR | White | 35.7 (5.5) | Group 1—Diet ( self selected from: 600k cal/d deficit by reducing portions; or traffic light system; or low carbohydrate diet ≤50 g/d with traffic light system) and exercise advice (web based) Group 2—Diet as above and exercise advice (basic nurse support) Group 3—Diet as above and exercise advice (regular nurse support) |
Group 4—Control |
1 kcal=4.18 kJ
*Median
†Range
ADAPT=arthritis, diet, and activity promotion trial; CLIP=community level interventions for pre-eclampsia; DASH=dietary approaches to stop hypertension; DGA=dietary guidelines for Americans; DPP=diabetes prevention program; DPS=diabetes prevention study; FFIT=football fans in training; GI=glycaemic index; Look AHEAD=look action for health in diabetes; NR=not reported; PRIDE=program to reduce incontinence by diet and exercise; PUFA/SFA=polyunsaturated fatty acids/saturated fatty acids; SD=standard deviation; TAIM=trial of antihypertensive interventions and management; TONE=trial of nonpharmacologic intervention in the elderly; TOHP=trials of hypertension prevention; VLCD=very low calorie diet.