Efficacy of a Homemade Very Low Calorie Diet to Achieve Prevention or Remission of Type 2 Diabetes: A Pilot Study

Introduction: Very low calorie diets have achieved remission of type 2 diabetes in obese individuals and lowered cardiovascular risk. However, there is less evidence for prevention of diabetes with these diets. Oxidative stress is a feature of obesity, diabetes and cardiovascular disease, but it is not clear what impact these diets have on oxidative stress in diabetes or prediabetes. Commercial meal replacement products may be expensive, so in this pilot study, we sought to explore the use of a homemade very low calorie diet to achieve weight loss in obese individuals with prediabetes or early onset type 2 diabetes and the effect on oxidative stress. Methods: Individuals with a BMI > 35 kg/m² and prediabetes or type 2 diabetes for less than 4 years followed a three-phase diet plan over 48 weeks, including a homemade meal replacement of 800 calorie for the first 12 weeks. Data was collected for weight, waist circumference, glycosylated HbA1_c, oxidised LDL and protein carbonyls at 12 weekly intervals. Quality of Life and Self-regulation of Eating Behaviour questionnaires were completed at 12 weekly intervals. Data was analysed using Friedman's test or mixed effects analysis for non-normally and normally distributed data respectively. Results: Of 22 individuals enroled at baseline, 16 completed the 12 week diet intervention phase and 12 completed 48 weeks. There were significant falls in weight (p < 0.001), and in waist circumference (p < 0.001) up to 36 weeks with mean weight loss of 15 kg at 48 weeks. HbA1_c fell significantly (p < 0.001) up to 24 weeks. By 48 weeks, 67% of participants were in the prediabetes or no diabetes categories. Oxidised LDL (p = 0.039) and protein carbonyls (p = 0.005) both increased significantly through the 12 week diet intervention and the ongoing study phases. There were significant improvements in Quality of Life (p = 0.005) and Self-regulation of Eating Behaviour (p < 0.0001) scores throughout the study. Conclusion: We have demonstrated that an inexpensive homemade very low calorie meal replacement as a weight loss tool has high levels of acceptability in addition to health and quality of life benefits in type 2 or prediabetes. The effect of very low calorie diets on inflammation and oxidative stress require further exploration.