Long-term effects of very low-carbohydrate diet with intermittent fasting on metabolic profile in a social media-based support group

Abstract

Very low-carbohydrate (VLC) diet with intermittent fasting (IF) have been shown to improve glycemic control and promote weight loss. However, their sustainability beyond 12 months has yet to be shown. This observational study aimed to assess sustainable weight loss and improvement in metabolic profile with such strategy in a self-motivated cohort. Subjects were recruited from a social media-based group who had to be on VLC±IF. Participants completed a questionnaire through on online survey tool. Participants voluntarily provided laboratory data pre-and post-lifestyle intervention. 63 patients participated in the study. Mean length on the diet was 35.8 months. Mean weight loss was 16.1 kg (|Z|-value 4.13, p<.0001). 53/63 (84.1%) respondents practiced IF. 18/63 (28.6%) reported fasting for 16 hours and eat within an 8-hour window whereas 15/63 (23.8%) reported fasting for 18 hours and eat within a 6-hour window. Mean carbohydrate intake was 10%. Change in mean glucose level was from 121.6 mg/dl to 90.4 mg/dl (|Z|-value 3.08, p 0.0034) and hemoglobin A1c from 6.87% to 5.2% (|Z|-value 3.96, p .0002). Triglycerides level showed reduction from 159.4 mg/dl to 98.4 mg/dl (|Z|-value 3.39, p 0.0012). HDL levels increased from 50.2 mg/dl to 66.9 mg/dl (|Z|-value 3.46, p<0.001) whereas total cholesterol level and LDL level increased from 206.3 mg/dl to 236 mg/dl (|Z|-value 1.94, p 0.0561) and from 138.4 mg/dl to 156.4 mg/dl (|Z|-value 1.68, p 0.0977) respectively. Participation of social media-based support group provides a unique opportunity to study the effects of different dietary and fasting approaches in real-world situations and is more likely to indicate the durability of such approaches. Although observational in nature with the caveat of self-reporting, the results are promising and call for larger, randomized trials.

When and what to eat? A scoping review of health outcomes of fasting in conjunction with a low-carbohydrate diet

“…Four studies with moderate to high-quality designs focused on the effect of an LCD and fasting on cardiovascular health and cardiovascular diseases [39][40][41]44]. All papers confirmed the benefits of LCD and fasting in improving the risk factors for cardiovascular diseases.…”

“…The haemoglobin A1c (HbA1c) levels decreased in 54% of participants. They also reported significant reductions in diagnostic parameters of plasma glucose in 40% of participants and fasting insulin in 14% of participants [40]. A second study, a high-quality prospective longitudinal study, reported a reduction in fasting insulin by 24% after six months of combining alternate-day fasting and LCD but found no change in participants fasting glucose, insulin resistance, or HbA1c levels [41].…”

“…All papers confirmed the benefits of LCD and fasting in improving the risk factors for cardiovascular diseases. The first study, a moderate-quality retrospective cross-sectional study, found that 56% of partici-https://doi.org/10.1017/S0007114522001854 Published online by Cambridge University Press pants' triglyceride levels improved, and high-density lipoprotein (HDL) cholesterol increased for 52% of participants [40]. They also reported that 71% of participants were able to discontinue their lipid-lowering medications.…”

“…The majority of these studies had moderate to high-quality designs, and all confirmed the beneficial impact of an LCD and fasting on weight loss and weight maintenance. A mean weight loss of 16 kilograms over three years was re-https://doi.org/10.1017/S0007114522001854 Published online by Cambridge University Press ported by Jacobi et al [40] in their moderate-quality retrospective cross-sectional study. Kalam et al [41] and the secondary analyses by Kalam et al [47,48]reported a net weight loss of 5.5% of body mass at three months and 6.3% after six months in their high-quality prospective longitudinal study.…”

“…Two studies reported that combining the two dietary patterns did not adversely affect sleep factors [47]. A moderate cross-sectional study by Jacobi et al [40] found a 24% reduction in participants reporting insomnia at the end of the intervention. A moderate-quality longitudinal study by Kalam et al [47] found no difference from baseline, three months, and six months in sleep quality, duration, insomnia, or the risk of apnoea.…”