Table 4.
A Summary of Relevant Outcomes and Main Findings in the Included Studies
| First Author, Publication Year, Country |
Primary Outcomes | Secondary Outcomes | Main Findings Related to Weight | Significance (P) | Mean Change in Weight Status (Body Weight in kg or BMI in kg/m2) |
|---|---|---|---|---|---|
| Barnard et al 200011 USA |
Serum total and LDL cholesterol concentrations | Weight | Reductions in weight and BMI. Participants who started the intervention first did not regain their original weight during the subsequent supplement phase. Changes in weight were associated with changes in energy intake | <0.001 | Intervention: −2,5 kg; −0,9 kg/m2 |
| Barnard et al 200512 USA |
Dietary intake, body weight and composition, resting metabolic rate, thermic effect of food, insulin sensitivity | Significant weight reduction in the vegan group, but no significant difference between the vegan and NCEP groups | =0.012 | Intervention: −5,8 kg ± 3.2 kg Control: −3,8 kg ± 2.8 kg |
|
| Barnard et al 200913 USA |
HbA1c, plasma lipids, weight | Sustained weight reductions in both the vegan and ADA groups, with no significant difference between the groups | =0.25 | Intervention: −4,4 kg (non-completers); −6,8 kg (completers) Control: −3,0 kg (non-completers); −4,9 kg (completers) |
|
| Barnard et al 201814 USA |
Body weight, HbA1c, plasma lipids, urinary albumin, BP | Weight reductions in both groups, with no significant difference between the groups | =0.10 for weight, =0.075 for BMI | Intervention: −6,3 kg; −2,3 kg/m2 Control: −4,4 kg; −1,5 kg/m2 |
|
| Elkan et al 200815 Sweden |
Blood lipids, oxLDL, anti-PC | BMI | Weight reductions in both groups, but the change was significant only in the intervention group | <0.001 | Intervention: −4,2 kg; −1,4 kg/m2 Control: −0,7 kg; −0,4 kg/m2 |
| Ferdowsian et al 201016 USA |
Changes in body weight, anthropometric measures, BP, lipid profile, dietary intake | Weight reductions only in the intervention group, the difference was significant between the groups. Sex, age, and changes in intake of total fat and fiber, were not significant predictors for weight loss | <0.001 | Intervention: −5,1 kg ± 0.6 kg; −2,0 kg/m2 Control: +0,1 kg ± 0.6 kg; −0 kg/m2 |
|
| Haugen et al 199317 Norway |
Nutritional status | Height, BMI, UAC, TSF | BMI was significantly lower in the intervention group compared with the control group | =0.04 | Intervention: −3.0 kg/m2 (among completers after 4 months) |
| Jakse et al 201718 Slovenia |
Body composition indices (body fat percentage, visceral fat, weight, muscle mass) | Significant reductions in weight and body fat with relative preservation of muscle mass | <0.001 | Intervention: −5,6 kg Control: −1,2 kg |
|
| Johansson et al 199219 Sweden |
Mutagenic activity in urine and feces | Weight | Mean weight reduction among the participants | <0.01 | Intervention: −2 kg |
| Kaartinen et al 200020 Finland |
VAS, joint stiffness, quality of sleep, questionnaires | BMI | Significant weight reductions in the intervention group. In the beginning of the study 66% of the participants were overweight. BMI in the intervention group was within normal values at the end of the study, and there was a clear increase after the intervention period | =0.0001 | Intervention: −4 kg/m2 Control: −0 kg/m2 |
| Kahleova et al 201821 USA |
Weight, body composition, insulin resistance | Reductions in weight and BMI only in the intervention group, which was associated with increased carbohydrate and fiber intake. The associations remained significant after adjustment for energy intake | <0.001 | Intervention: −6,5 kg; −2,0 kg/m2 Control: +0,57 kg |
|
| Kahleova et al 201822 USA |
Weight, body composition, insulin resistance | Reductions in weight and BMI only in the intervention group, which was associated with increased intake of plant protein | <0.001 | Intervention: −6,5 kg; −2,0 kg/m2 Control: +0,57 kg |
|
| Mishra et al 201325 USA |
Dietary intake, body weight, plasma lipids, BP, HbA1c | Weight reductions in the intervention group, with significant difference between the groups | <0.001 | Intervention: -2,9 kg (non-completers) -4,3 kg (completers) -1,04 kg/m2 (non-completers) -1,5 kg/m2 (completers) Control: -0,06 kg (non-completers) -0,08 kg (completers) -0,01 kg/m2 (non-completers) 0.02 kg/m2 (completers) |
|
| Moore et al 201526 USA |
Diet adherence, weight loss, changes in animal products intake by adherence status | Significantly greater weight loss among non-adherent vegan/vegetarian participants compared with non-adherent omnivore participants. However, there was no difference in weight loss among participants who adhered to their diet, regardless of the diet | =0.04 | Intervention: −6,0 ± 6.7% (non-adherent participants) Control: −0,4 ± 0.6% (non-adherent participants) |
|
| Pischke et al 201927 USA |
Medical characteristics (height, weight, percentage body fat, BP, angina pectoris, plasma lipids), lifestyle, quality of life | Significant weight reductions in all participants, regardless of sex and diabetic status | <0.001 | Intervention: −5 kg | |
| Sofi et al 201928 Italy |
Difference in body weight, BMI, and fat mass changes between the groups | Difference in cardiovascular risk parameters changes between the groups | Significant weight reductions in both groups, with no significant difference between the groups | Intervention: −1,88 kg; −0,64 kg/m2 Control: −1,77 kg; −0,67 kg/m2 |
|
| Toobert et al 200029 USA |
Changes in cardiovascular risk factors: lipid profile, BMI, BP, medications, quality of life | Significant reductions in BMI in the intervention group compared with the control group | =0.041 | Intervention: −3,9 kg (12 months); −1 kg/m2 (24 months) Control: −0,06 kg (12 months); −0 kg/m2 (24 months) |
|
| Turner-McGrievy et al 200730 USA |
Weight loss maintenance and diet adherence | Significantly greater weight reduction in the intervention group compared with the NCEP group after 1 and 2 years | <0.05 | Intervention: −4,9 kg (1 year); −3,1 kg (2 year) Control: −1,8 kg (1 year); −0,8 kg (2 year) |
|
| Turner-McGrievy et al 201531 USA |
Weight loss | Significantly greater weight loss in the vegan group compared to the pesco-vegetarian, semi-vegetarian and omnivore groups | <0.01 | −7,5% vegan -6,3% vegetarian -3,1% omnivore |
|
| Wright et al 201732 New Zealand |
BMI, cholesterol | Significant weight reductions in weight and BMI in the intervention group compared with the control group | <0.0001 | Intervention: -12,1 kg (6 months) -11,5 kg (12 months) -4,4 kg/m2 (6 months) -4,2 kg/m2 (12 months) |
Abbreviations: BMI, body mass index; HbA1c, glycated hemoglobin; oxLDL, oxidized low-density lipoprotein; anti-PC, anti-phosphorylcholine; ADA, American Diabetes Association; T2DM, type 2 diabetes mellitus; BP, blood pressure; UAC, upper arm circumference; TSF, triceps skin fold; VAS, visual analog scale; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; WBC, white blood cells; NCEP, National Cholesterol Education Program; WFPB, whole-food plant-based.