Researchers tested five different eating patterns on 96 people with obesity to see which one lowered blood pressure the most. They compared eating only during certain hours of the day, skipping meals every other day, following a ketogenic (keto) diet, and eating a Mediterranean diet. After the study, people who practiced modified alternate-day fasting (eating normally one day, then eating very little the next day) had the biggest improvements in their blood pressure readings. Interestingly, the keto diet didn’t work as well as expected, even though it’s often promoted for weight loss and health benefits. All the diets helped people lose weight, but the alternate-day fasting approach was the clear winner for blood pressure control.

The Quick Take

  • What they studied: Whether five different eating patterns could lower blood pressure in people with obesity, measured using 24-hour blood pressure monitors that track changes throughout the day and night.
  • Who participated: 96 adults with obesity (BMI over 30) were randomly divided into five groups, each following a different eating plan for a set period. The study measured their blood pressure before and after the intervention.
  • Key finding: Modified alternate-day fasting (eating normally one day, then eating very little the next day) produced the biggest improvements in 24-hour blood pressure readings compared to other diets, including the popular ketogenic diet.
  • What it means for you: If you have high blood pressure and obesity, alternate-day fasting may be more effective than other popular diets for lowering your numbers. However, this was a small study, and you should talk to your doctor before starting any new eating plan, especially one that involves skipping meals.

The Research Details

This was a randomized controlled trial, which is one of the strongest types of scientific studies. Researchers took 96 people with obesity and randomly assigned them to five different groups. One group followed a modified alternate-day fasting plan (eating normally one day, then eating very little the next). Two groups practiced time-restricted eating, where they only ate during certain hours of the day—one group ate early in the day, the other ate later. One group followed a ketogenic (keto) diet, which is very low in carbs. The last group followed a standard Mediterranean diet as a control group to compare against. Before and after the diet period, all participants wore special blood pressure monitors that recorded their readings every 30 minutes for 24 hours, capturing blood pressure during sleep, work, and daily activities.

This approach is better than just checking blood pressure once at a doctor’s office because it shows how blood pressure changes throughout the day and night. The researchers also measured body weight, body fat, and other health markers to understand how these changes related to blood pressure improvements.

The study was well-designed because it randomly assigned people to groups, which helps prevent bias. All participants were measured the same way before and after, and the researchers used statistical methods to account for differences between groups.

Most blood pressure studies only measure pressure once in a clinic, which can give misleading results because blood pressure naturally changes throughout the day. This study used 24-hour monitoring, which is more accurate and shows real-world blood pressure patterns. This matters because some people have high blood pressure only at certain times of day, and some diets might work better for controlling pressure during sleep versus during active hours. Understanding which eating pattern works best for overall blood pressure control helps doctors and patients make better choices.

This study has several strengths: it was randomized (reducing bias), it included a control group for comparison, it used objective 24-hour blood pressure monitoring (not just single readings), and it measured multiple health markers. However, the sample size of 96 people is relatively small, and the study only included people with obesity, so results may not apply to everyone. The study was published in a reputable journal (European Journal of Preventive Cardiology), which suggests it met high scientific standards. One limitation is that we don’t know how long the benefits lasted after the study ended.

What the Results Show

All five diet groups showed improvements in weight and body measurements, which is expected when people eat fewer calories. However, when researchers looked specifically at blood pressure changes measured over 24 hours, the results were different. The modified alternate-day fasting group showed the most improvement in blood pressure readings, with better numbers throughout the day and night. The evening time-restricted eating group (eating only later in the day) showed some improvements, but smaller ones. Surprisingly, the ketogenic diet group, the early time-restricted eating group, and the Mediterranean diet control group did not show statistically significant improvements in their 24-hour blood pressure readings, even though they lost weight.

When researchers analyzed the data using advanced statistical methods, they found that modified alternate-day fasting had the strongest effect on lowering 24-hour systolic blood pressure (the top number in a blood pressure reading). This was true even after accounting for how much weight people lost. Interestingly, the amount of body fat lost was linked to blood pressure improvements across all groups, suggesting that losing fat specifically (not just overall weight) matters for blood pressure control.

The study also found that age and sex didn’t significantly affect how well the diets worked. This means the results applied fairly equally to both men and women and to people of different ages within the study group.

Beyond the main blood pressure findings, the study measured other important health markers. All groups improved their weight and body composition, but the alternate-day fasting group had the greatest overall improvements. The researchers noted that the ketogenic diet’s theoretical advantage (producing ketones, which are thought to have health benefits) didn’t translate into better blood pressure control compared to other approaches. This suggests that for blood pressure specifically, how often you eat may matter more than what type of food you eat. The study also showed that the relationship between losing body fat and lowering blood pressure was consistent across all diet types, indicating that the mechanism of blood pressure improvement is primarily through fat loss rather than through specific dietary components.

Previous research has shown that weight loss generally helps lower blood pressure in people with obesity, but there’s been limited evidence comparing different diet types directly. Some earlier studies suggested ketogenic diets might have special blood pressure-lowering benefits beyond simple weight loss, but this study challenges that idea. The finding that alternate-day fasting works better than keto is somewhat surprising given keto’s popularity for weight loss. This research adds to growing evidence that the timing of eating and the pattern of calorie restriction may be as important as the specific foods chosen. The study supports previous findings that losing body fat (rather than just losing weight from water or muscle) is key to improving blood pressure.

This study has several important limitations to consider. First, only 96 people participated, which is a relatively small number. Second, all participants had obesity, so we don’t know if these results apply to people of normal weight or to people with different health conditions. Third, the study was conducted at a single center, which might mean the results reflect that specific population or setting. Fourth, we don’t know how long the blood pressure improvements lasted after the study ended—did people maintain the benefits, or did blood pressure return to baseline? Fifth, the study didn’t measure how well people stuck to each diet, which could affect results. Finally, the study period wasn’t specified in the abstract, so we don’t know if this was a short-term or long-term intervention.

The Bottom Line

If you have high blood pressure and obesity, modified alternate-day fasting appears to be more effective than other popular diets for lowering blood pressure (moderate confidence based on this single study). However, before starting any new eating plan, especially one involving fasting, consult with your doctor or a registered dietitian. They can help determine if this approach is safe for you and can monitor your blood pressure and overall health. The Mediterranean diet and time-restricted eating may also help, though they showed smaller benefits in this study. The key takeaway is that losing body fat through any reduced-calorie diet helps lower blood pressure, but alternate-day fasting may offer additional benefits.

This research is most relevant to adults with obesity (BMI over 30) who have high blood pressure or want to prevent it. It may also interest people looking for effective weight loss strategies. However, people with certain medical conditions (like diabetes, eating disorders, or heart conditions), pregnant or breastfeeding women, and those taking specific medications should not start alternate-day fasting without medical supervision. If you have normal blood pressure and healthy weight, these findings may be less directly applicable to you, though maintaining a healthy weight is always beneficial.

Based on this study, blood pressure improvements appeared after completing the full intervention period, though the exact duration wasn’t specified in the abstract. Realistically, you shouldn’t expect immediate changes—blood pressure typically takes weeks to months to improve with diet changes. Most people see noticeable improvements within 4-12 weeks of consistent effort, but individual results vary. It’s important to monitor your blood pressure regularly (ideally with a home monitor) to track your progress and share results with your doctor.

Want to Apply This Research?

  • Use your app to log your eating pattern (which diet approach you’re following), daily weight, and weekly blood pressure readings taken at the same time each day. Create a simple tracker showing: eating window/fasting days, weight trend, and systolic/diastolic blood pressure. Set a goal to see if your blood pressure drops by 5-10 mmHg over 8-12 weeks.
  • If trying alternate-day fasting, use your app to set reminders for eating and fasting days, log your meals on eating days to ensure adequate nutrition, and track how you feel during fasting periods. Create a simple checklist: Did I follow my eating pattern today? Did I drink enough water? How was my energy level? This helps you stay consistent and identify any challenges.
  • Set up weekly blood pressure check-ins in your app (same day, same time each week for consistency). Create a simple graph showing your blood pressure trend over weeks and months. Also track body weight weekly and body measurements monthly. Share this data with your doctor at regular appointments to ensure the diet approach is working safely for you and to adjust if needed.

This research summary is for educational purposes only and should not replace professional medical advice. The study involved people with obesity and may not apply to everyone. Before starting any new diet, especially one involving fasting or significant calorie restriction, consult with your doctor or a registered dietitian. This is particularly important if you have high blood pressure, diabetes, heart disease, take medications, are pregnant or breastfeeding, or have a history of eating disorders. Your doctor can monitor your blood pressure and overall health to ensure any dietary changes are safe and effective for your individual situation. Do not stop or change blood pressure medications without medical guidance.