Healthy plant-based diets and their short-term effects on weight loss, nutrient intake and serum cholesterol levels

Abstract

Healthy plant-based diets (hPBD) are being promoted to reduce the risks of cardiovascular and associated diseases. This study investigates short-term adherence to a hPBD to examine whether these dietary changes impact weight and cardiovascular risk factors. A simple, uncontrolled, before and after design was used. Twenty women (mean BMI 31 ± 4 kg/m² ) participated in a 6-week hPBD intervention. Participants completed a 3-week reset, eliminating all refined sugar, heavily processed foods, artificial sweeteners, alcohol, meat, fish, dairy and oil from their diets, which could then be reintroduced into their diet if the participant chose to do so. Participants had 1-h, weekly group support sessions. A weight loss of 4.4 kg, SD = 1.8 kg (n = 17, t = 10.2, p < 0.001) was observed after 6 weeks following the hPBD. BMI reduced from 31 to 29 kg/m² (mean reduction = 1.38, SD = 0.76, n = 17, t = 7.49, p < 0.001). Reductions for waist circumference (mean reduction = 4.4 cm, SD = 5.22 cm, n = 8, t = 2.55, p = 0.034), LDL cholesterol (mean reduction = 0.600 mmol/L, SD = 0.828, n = 17, t = 2.81, p = 0.014) and total cholesterol (mean = 0.525 mmol/L, SD = 0.969, n = 17, t = 2.24, p = 0.040) were also observed. Body fat % was not significantly reduced (mean reduction = 2.3, SD = 6.6, n = 17, t = 1.49, p = 0.154). Dietary data were obtained from 17 participants at week 3 and from six participants at week 6. Energy intake at week 3 decreased compared with baseline (mean reduction = 1068 kcal/day, SD = 585 kcal, n = 17, t = 7.07, p < 0.001) and at week 6 (mean reduction = 715 kcal, SD = 645 kcal, n = 6, t = 2.72, p = 0.042). Protein, saturated fat and cholesterol intakes were also lower at weeks 3 and 6 compared with baseline. Fibre intake increased significantly from baseline to week 6 (mean increase = 11.3 g/day, SD = 8.9, n = 6, t = 3.11, p = 0.027) whilst sugar intake decreased from baseline to week 3 (mean reduction = 26.0 g/day, SD = 22.3, n = 17, t = 4.52, p < 0.001), but the reduction at week 6 was not significant. These results suggest that motivated participants can learn to adopt new dietary patterns for a few weeks at least with some support. This study demonstrated positive effects of a hPBD on weight reduction, cholesterol and BMI over a short time period, although the short- and long-term adherence to this diet requires further research.

Keywords: BMI; LDL cholesterol; cardiovascular disease; obesity; plant-based diets; saturated fat.