Cardiovascular Disease, Obesity, Metabolic Syndrome, General Health

Low-Calorie, High-Protein Ketogenic Diet Versus Low-Calorie, Low-Sodium, and High-Potassium Mediterranean Diet in Overweight Patients and Patients with Obesity with High-Normal Blood Pressure or Grade I Hypertension: The Keto-Salt Pilot Study

This pilot study examined the effects of two calorie-restricted diets on blood pressure and metabolic health in overweight or obese adults with mildly elevated blood pressure. Over a 3-month period, participants followed either a ketogenic diet (KD) or a Mediterranean diet (MD). The primary goal was to evaluate changes in 24-hour ambulatory blood pressure; secondary outcomes included body composition and metabolic markers.

A total of 26 adults with central adiposity and no diabetes were enrolled: 15 in the KD group and 11 in the MD group. Both diets provided around 1,300 kcal per day. The KD was very low in carbohydrates (<50 g/day), moderate in protein (≥1.2 g/kg ideal body weight), and high in fat, with higher sodium (5–8 g/day) and lower potassium (<4 g/day). The MD was moderate in carbohydrates (≥50 g/day), protein (0.9 g/kg ideal body weight), and fat, with lower sodium (<5 g/day) and higher potassium (4 g/day). All meals were prepared from whole foods, without supplements.

Key Findings:

Blood Pressure (BP)

• 24-hour systolic BP dropped from 125.0 to 116.1 mmHg; diastolic from 79.0 to 73.7 mmHg overall.
• Both diets lowered daytime and night-time BP, with no difference between diets in average BP reduction.
• Night-time BP “dipping” improved in the KD group (+2.6%) but worsened in the MD group (−6.0%)

Weight and Body Composition

• Average weight loss was 25 pounds (11.3 kg) in the KD group and 17 pounds (7.7 kg) in the MD group.
• Fat mass decreased, fat-free mass percentage increased, and waist circumference decreased in both groups.

Metabolic Markers

• Fasting insulin and HOMA-IR decreased significantly in both groups.
• Triglycerides, total cholesterol, LDL-C, and non-HDL-C improved in both groups.
• Fasting glucose and HbA1c decreased in both groups.
• No significant differences between diets.

Body Composition & BP Correlation

• Improvements in systolic BP were moderately associated with greater fat mass loss relative to lean mass (∆FM/∆FFM ratio).

Three months of a hypocaloric ketogenic or Mediterranean diet led to similar improvements in body weight, blood pressure, and metabolic health in adults with overweight/obesity and mildly elevated blood pressure. Reducing fat mass was a key factor in blood pressure improvement. The KD group showed greater enhancement in nocturnal BP dipping, suggesting a possible added benefit that merits further study.