Introduction: Recent randomised controlled trials have demonstrated the efficacy of very low calorie diets (VLCD) in carefully selected patients with type 2 diabetes mellitus (T2DM). However, there is paucity of evidence regarding the efficacy of VLCD in the real-world setting. We evaluated outcomes in obese T2DM patients who underwent VLCD at our institution.
Methods: This retrospective observational study included all patients who had undergone VLCD from August 2014 to December 2017 (n=61). The VLCD programme consisted of an eight-week 800 kcal/day dietary restriction (600 kcal meal replacements plus 200 kcal vegetable dish) accompanied by structured education. Metabolic parameters and medications were recorded at baseline, immediately post-VLCD, six and twelve months post-VLCD. The primary outcome was reduction in weight at twelve months post-VLCD.
Results: The mean age of patients was 55.2 years (range 3675 years). The mean starting weight was 108.2 kg. There was a significant reduction in weight of 9.96 kg (P<0.001) immediately post-VLCD, with net weight loss sustained to twelve months (P<0.05). The mean starting body mass index (BMI) was 38.2 kg/m2. There was a significant reduction in BMI sustained to twelve months (P<0.05). The mean starting HbA1c was 79.60 mmol/mol. There was a significant reduction in HbA1c of 13.29 mmol/mol immediately post-VLCD (P<0.001) which did not sustain at six or twelve months. 78.7% patients had a reduction in T2DM medication burden post-VLCD, sustained in 44.3% patients at twelve months. 6/23 (26.1%) patients who were on insulin pre-VLCD, no longer required it at twelve months. Analysis of patients with T2DM diagnosis duration >6 years demonstrated statistically significant weight loss sustained to twelve months (P<0.001).
Conclusion: To our knowledge, this is the first study reporting outcomes of VLCD in obese patients with a diagnosis of T2DM for >6 years. Our results demonstrate sustained reduction in BMI and weight, reduction in medication burden and temporary reduction in HbA1c.