A ketogenic diet can lower blood pressure, though the effect is modest and not clearly superior to other weight-loss diets. Most clinical trials show reductions of 2 to 10 points in systolic blood pressure (the top number) over 3 to 12 months, with the largest drops happening in the first few months. The 2025 joint guidelines from the American Heart Association and American College of Cardiology list low-carbohydrate diets among eating patterns shown to reduce blood pressure, while noting they are less effective than the DASH diet specifically designed for hypertension.
What the Clinical Trials Actually Show
Several randomized controlled trials have tested very low-carb diets (under 50 grams of carbohydrates per day) against other approaches, and the blood pressure results are mixed. A 20-month trial of 311 overweight women found the Atkins-style group had the largest blood pressure decrease at every time point: 7.6 mmHg systolic and 4.4 mmHg diastolic by the end of the study. That’s a meaningful drop, roughly equivalent to what some people get from a single blood pressure medication at a low dose.
But other trials tell a less impressive story. A 12-month study of 63 obese adults found no significant difference in blood pressure between a low-carb group and a conventional low-fat group, with the low-carb group averaging just a 2.7 mmHg systolic drop. A separate 12-month trial comparing Atkins, Zone, Weight Watchers, and Ornish diets in 160 adults with known hypertension found no significant blood pressure differences between any of the groups. And a two-year study of 307 participants comparing low-carb to low-fat diets found similar small reductions in both groups, with no advantage for either approach.
One observational study of 377 outpatients on a very low-carb ketogenic diet showed a more encouraging pattern: systolic pressure dropped by an average of 10.5 mmHg and diastolic by 2.2 mmHg within three months. But no further improvements occurred between three and twelve months, suggesting most of the benefit came early.
Why Keto Affects Blood Pressure
When you sharply cut carbohydrates, your insulin levels drop. Insulin normally tells your kidneys to hold onto sodium. With less insulin circulating, your kidneys release more sodium into your urine, and water follows. This is why people often lose several pounds of water weight in the first week of keto, and it’s also why blood pressure tends to dip early on. The effect mirrors what happens in type 1 diabetes, where very low insulin levels cause increased sodium and water loss through the kidneys.
Weight loss itself is likely the bigger driver over time. Losing even 5 to 10 pounds consistently lowers blood pressure regardless of how you lose it. Since keto diets tend to suppress appetite and produce rapid early weight loss, people often see blood pressure improvements that have more to do with the pounds lost than with ketosis specifically. This helps explain why head-to-head trials rarely find a clear winner between keto and other calorie-matched diets for blood pressure.
Animal research has also found that ketogenic diets may dial down the body’s renin-angiotensin-aldosterone system, a hormonal network that raises blood pressure by tightening blood vessels and retaining sodium. In mice, a ketogenic diet reduced the activity of the pro-inflammatory branch of this system. Whether this translates directly to humans is still uncertain, but it offers a plausible additional mechanism.
The Sodium Paradox on Keto
Here’s where things get tricky. Standard advice for lowering blood pressure calls for eating less sodium, typically under 2,300 mg per day. But many keto guides recommend the opposite: adding extra salt to compensate for the sodium your kidneys flush out during ketosis. In one pilot study comparing a ketogenic diet to a Mediterranean diet in people with high-normal blood pressure, the keto group consumed 5 to 8 grams of sodium per day (more than double what hypertension guidelines recommend), while the Mediterranean group stayed under 5 grams.
If you’re following keto specifically to improve blood pressure, this tension matters. Too little sodium on keto can cause dizziness, fatigue, and headaches as your body adapts. Too much can work against the blood pressure benefits you’re trying to achieve. Potassium intake adds another layer of complexity. The keto diet naturally limits many potassium-rich foods like bananas, potatoes, and beans. In the same pilot study, the keto group consumed less than 4 grams of potassium daily, while the Mediterranean group hit 4 grams. Potassium helps your body excrete sodium and relax blood vessel walls, so falling short can undermine blood pressure control.
Effects on Blood Vessel Health
Blood pressure numbers don’t tell the whole story. Two studies in children and young adults on ketogenic diets (used medically for epilepsy) found that the diet increased arterial stiffness, meaning the walls of the carotid arteries became less flexible. Stiffer arteries are an early marker of cardiovascular risk, even when blood pressure looks normal on paper.
The reassuring finding: these changes appeared to be temporary. In one study tracking 43 children over two years, carotid artery flexibility worsened at 3 and 12 months but returned to normal by 24 months. The actual thickness of the artery walls never changed. Both research teams reached similar conclusions: the ketogenic diet causes some initial arterial stiffening that declines over time and appears reversible. Still, these studies involved therapeutic ketogenic diets with very high fat ratios (4 parts fat to 1 part everything else), which are more extreme than what most adults follow for weight loss.
How Keto Compares to Other Diets
The DASH diet remains the most studied and consistently effective dietary approach for blood pressure. It emphasizes fruits, vegetables, whole grains, and low-fat dairy while limiting sodium and saturated fat. The AHA’s 2025 guidelines rank it above low-carbohydrate diets for blood pressure reduction.
That said, the “best” diet for your blood pressure is the one you’ll actually follow. Keto works well for people who find it easier to cut carbs than count calories, and the rapid early results can be motivating. If you lose 15 or 20 pounds on keto that you wouldn’t have lost on another plan, the blood pressure benefit from that weight loss is real and significant regardless of the dietary mechanism. A 24-month trial of 113 participants found that all three diet groups (very low-carb, very low-fat, and high unsaturated fat) lowered diastolic pressure by about 3 mmHg compared to the control group that made no changes. The takeaway: dieting beat not dieting, and no single approach dominated.
Practical Considerations
If you’re already on blood pressure medication and start a ketogenic diet, your blood pressure may drop faster than expected, especially in the first few weeks as your body sheds water and sodium. This can cause lightheadedness or fainting, particularly when standing up quickly. Your medication dose may need adjusting, so tracking your readings at home gives you useful data to share with your doctor.
Prioritizing potassium-rich foods that fit within keto is worth the effort. Avocados, spinach, mushrooms, and salmon are all good options that keep you under your carb limit while supporting healthy blood pressure. Salting food to taste is reasonable during keto adaptation, but routinely adding large amounts of salt to chase electrolyte targets can be counterproductive if blood pressure is your primary concern.
The strongest blood pressure benefits from keto appear in the first three months and track closely with weight loss. If you plateau on weight, you’ll likely plateau on blood pressure improvement too. For people who are overweight with mildly elevated blood pressure, keto is a reasonable choice among several effective dietary strategies. For those with significantly high blood pressure, the sodium question and the limited long-term advantage over other diets make it worth considering whether a DASH-style approach might be a more direct path to the numbers you want.