Key Takeaway
Keto improved HDL and triglycerides in type 2 diabetes but showed no additional benefit for blood sugar control or weight loss compared to control diets over two years.
Summary
This meta-analysis of 11 RCTs (19 reports, 2001-2021) compared ketogenic diets to control diets in adults with type 2 diabetes for interventions lasting more than 14 days.
The headline finding was negative for keto's primary claimed benefits: no significant difference in glycemic control (HbA1c) or body weight compared to control diets. However, keto did improve lipid profiles — HDL cholesterol increased (SMD 0.19, moderate-quality evidence) and triglycerides decreased (SMD -0.41, low-quality evidence).
This is an important reality check: while keto may improve certain cardiovascular markers in diabetics, it doesn't outperform standard dietary approaches for the primary goals of blood sugar management and weight loss over longer timeframes.
Methods
- Systematic review and meta-analysis of 11 RCTs (19 reports)
- Adults with type 2 diabetes, interventions >14 days
- Compared ketogenic diet to control diets
- Published 2001-2021
Key Results
- HbA1c: no significant difference vs control
- Body weight: no significant difference vs control
- HDL cholesterol: increased (SMD 0.19, 95% CI 0.02-0.37, moderate quality)
- Triglycerides: decreased (SMD -0.41, 95% CI -0.64 to -0.18, low quality)
Limitations
- Only 11 RCTs met criteria
- Heterogeneous control diets across studies
- Most studies were short-term; up to 2 years maximum