A ketogenic diet can lower blood pressure in some people, but the overall evidence is mixed. A large meta-analysis of 23 randomized controlled trials involving 1,664 participants found that ketogenic diets did not produce a statistically significant reduction in either systolic or diastolic blood pressure. Yet individual trials tell a more nuanced story, and the answer depends heavily on your starting point, what you eat, and whether you lose weight in the process.
What the Clinical Trials Actually Show
The most comprehensive look at this question comes from a 2024 meta-analysis that pooled data from 23 controlled trials. Across all those studies, the average blood pressure drop on keto was less than 1 mmHg for both systolic and diastolic readings. That’s not clinically meaningful. Subgroup analyses looking at different fat intakes and study durations didn’t change the picture.
However, one well-designed trial compared a very low-carb diet directly against the DASH diet, which is widely considered the gold standard eating pattern for blood pressure control. In that study of overweight adults who already had hypertension and either prediabetes or type 2 diabetes, the very low-carb group saw their systolic blood pressure drop by 9.8 mmHg, compared to 5.2 mmHg in the DASH group. That 4.6 mmHg difference was statistically significant and surprised many researchers, since DASH was specifically designed for blood pressure.
The likely explanation for the discrepancy: the people who benefit most from keto are those who are overweight and insulin resistant. If you already have normal blood pressure and healthy metabolic markers, keto probably won’t move the needle. If you’re carrying extra weight and your body is overproducing insulin, the diet may address root causes that other approaches don’t.
Why Keto Affects Blood Pressure Early On
Many people notice a blood pressure drop in the first week or two of keto, but most of this is related to water and sodium loss rather than lasting cardiovascular change. When you cut carbohydrates sharply, your body’s 24-hour insulin output drops by more than 50%. Insulin normally signals the kidneys to hold onto sodium, so when insulin falls, the kidneys start flushing sodium and water. This effect is strongest during days one through four and stops almost immediately if you eat carbohydrates again.
This is why the scale drops quickly at the start of keto. It’s also why people experience “keto flu,” with symptoms like headaches, fatigue, and dizziness. That fluid loss can temporarily lower blood pressure, sometimes enough to cause lightheadedness, especially if you’re already taking blood pressure medication.
The Sodium Balancing Act
Here’s where things get tricky for people with high blood pressure. Popular keto resources routinely recommend consuming 2,000 to 5,000 mg of sodium per day to offset the fluid and electrolyte losses that come with carbohydrate restriction. But standard dietary guidelines for hypertension recommend staying under 2,300 mg per day, precisely because excess sodium raises blood pressure.
There’s no formal guideline that resolves this tension. Researchers studying ketogenic diets in people with kidney disease and hypertension have suggested keeping sodium under 2,300 mg daily (but not below 1,500 mg) and treating keto-flu symptoms first with magnesium, potassium, and extra fluids rather than reaching for the salt shaker. That approach prioritizes blood pressure control while still preventing the worst of the transition symptoms.
Medication Adjustments May Be Needed
If you take blood pressure medication and start a ketogenic diet, your readings may drop enough to require a dosage change. In one medical audit of patients placed on a carbohydrate-restricted diet, 35% were taking blood pressure medication at the start. Of those, 64% were eventually able to reduce or stop some or all of their medications. Some patients needed weekly monitoring for the first one to two months, while others only required check-ins every three to four months.
This is particularly important because the combination of blood pressure medication and the natural fluid loss from keto can cause your pressure to drop too low, leading to dizziness or fainting. If you’re on medication, your prescriber should be aware you’re making this dietary change so they can adjust your doses proactively rather than reactively.
Concerns About Arterial Health
Blood pressure is only one measure of cardiovascular health, and some research raises questions about what keto does to your blood vessels over time. Studies in children and young adults on ketogenic diets found increased arterial stiffness, higher cholesterol, and higher triglycerides compared to controls. Arterial stiffness is an early marker of cardiovascular risk that shows up before visible changes in blood vessel walls.
One study tracking artery health over time found that the carotid arteries became less flexible at 3 and 12 months on the diet but returned to normal by 24 months, with no lasting change in vessel wall thickness. That’s somewhat reassuring, but the long-term picture remains incomplete.
The American Heart Association scored 10 popular diets for heart health on a scale of 1 to 100. The ketogenic diet landed at 31, in the lowest tier, primarily because it doesn’t limit saturated fat and is difficult for most people to maintain long-term. The DASH, Mediterranean, pescetarian, and vegetarian patterns all scored significantly higher.
Who Might Benefit Most
The strongest case for keto and blood pressure comes from people who have a cluster of metabolic problems: excess weight, insulin resistance, prediabetes or type 2 diabetes, and elevated blood pressure. In this group, the drop in insulin levels and the resulting weight loss can produce meaningful blood pressure improvements that go beyond what the averaged-out meta-analysis numbers suggest.
If your blood pressure is your primary concern and you don’t have significant insulin resistance or weight to lose, the DASH diet has a much stronger evidence base and is easier to follow long-term. It emphasizes fruits, vegetables, whole grains, and low-fat dairy while limiting sodium, and it consistently produces blood pressure reductions of 8 to 14 mmHg in people with hypertension.
For people who do choose keto, the version that matters is one built around unsaturated fats (olive oil, avocados, nuts, fatty fish) rather than butter, bacon, and cheese. Keeping sodium moderate, prioritizing potassium-rich low-carb vegetables, and monitoring your blood pressure at home gives you the best chance of seeing benefits without trading one cardiovascular risk for another.