Objective : Low-carbohydrate diet with variable proportions of fat and protein have been shown to improve glycemic control and promote weight loss. However, their sustainability has yet to be shown. This study aims to assess whether a low carbohydrate diet with intermittent fasting in a self-motivated cohort leads to sustainable weight loss and improvement in metabolic profile.
This is an observational study including patients recruited from a social media-based group “Lower Insulin”. Interested respondents had to be on a low-carbohydrate diet +/- intermittent fasting. Respondents were sent a questionnaire through on online survey tool. Participants voluntarily provided laboratory data on their metabolic parameters 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 (90.1 kg at baseline to 73.9 kg, t-value 4.26, p < .0001). 84.1% respondents practiced intermittent fasting either for 16 hours and eat within an 8-hour window or for 18 hours and eat within a 6-hour window. Mean carbohydrate intake was 10% whereas mean fat and protein intake were 50.1% and 38.8% respectively. Changes in mean glucose level were from 121.6 mg/dl to 90.4 mg/dl (t-value 2.39, p 0.02) and hemoglobin a1c from 6.87 % to 5.2 % (t-value 3.79, p < 0.0001). Triglycerides level showed reduction from 159.4 mg/dl to 98.4 mg/dl (t-value 2.4, p 0.01). HDL levels increased from 50.2 mg/dl to 66.9 (t-value, -3.92, p < 0.001) whereas total cholesterol level increased from 206.3 to 236 (t-value -2.15, p 0.03) and LDL level increased from 138.4 to 156.4 (t-value – 1.38, p 0.1722). 75% had either stopped or reduced the number of diabetes medications.
Among non-metabolic parameters, there was an improvement in self-reported insomnia from 32.26% to 8.1% (odds ratio 6.6, CI 1.166 - 38.13). There was no significant improvement in self-reported memory loss, arthralgia and incidence of hepatic steatosis.
This study demonstrated a sustainable weight loss, improvement in glycemic control, triglycerides level, HDL cholesterol, reduction in the need for diabetes medications but increase in LDL and total cholesterol. Participation of social media-based support group provides a unique opportunity to study the effects of dietary and fasting approaches in a real-world situations and are more likely to indicate the durability of such approaches.
To our knowledge this is the first study showing that a low carbohydrate diet with intermittent fasting is effective in long-term. Although observational in nature, the results are promising and call for larger, randomized trials.