Blood pressure is the measurement of the force your blood exerts on your arteries as it moves throughout your body. Normally this pressure rises and falls throughout the day. But when it stays consistently elevated it may damage your heart and cause other health problems.
When the American Heart Association (AHA) and other health organizations changed the definition of high blood pressure,1 a large influx of people who had once been considered healthy were suddenly diagnosed with high blood pressure.
Using the new measurement of 130/80, the AHA estimates 103 million American adults have high blood pressure.2 It's called the “silent killer”3 since the only way to know if you have it is to have it measured. Getting it under control may be one of the best ways to protect your health.
High blood pressure increases the force against large and small blood vessels, which is one explanation for the damage it causes. It is linked to the development of heart disease, cognitive decline and dementia,4 kidney disease, vision loss and stroke.5
Fasting Has a Positive Effect on Blood Pressure
In the early 2000s, scientists investigating the health benefits of fasting found that the fasted state not only reduced blood pressure in a group of 174 study participants, but that the effects lasted longer than anticipated. Those whose blood pressure measured higher than 140/90 underwent an intervention of a medically supervised water-only fast for an average of 10 to 11 days.6
For two to three days before the fast began, their diet was limited to fruits and vegetables. Following the fast the researchers found 89% of the participants had a blood pressure measuring less than 140/90, which was the cutoff for high blood pressure at the time of the study.
The average reduction was a large jump of 37/13 and those who had the greatest reduction were those with the highest blood pressure. Participants whose pressure was higher than 180/110 experienced an average reduction of 60/17 by the end of the study.
A further reduction in blood pressure was experienced after the participants began eating, suggesting the fast may have started normalizing pressure that could be sustained.
The researchers followed up with 42 of the participants after 27 weeks and found the mean blood pressure for the group was a healthy 123/77. They concluded that while no generalizations could be made, the results do suggest those with high blood pressure may enjoy sustainable benefits when they continue to eat a balanced diet.
Fasting Affects Lipids and Insulin Regulation
In another small pilot study7 from 2017, researchers published similar results in people with Type 2 diabetes. Participants underwent a one-week Buchinger fast — a type of fast where participants burn their own fat as their body's fuel8 — during which they were allowed 300 calories per day of liquids only and then they were allowed a stepwise reintroduction of foods.
There were 32 who completed the trial. After four months the mean weight of those in the fasting group decreased by 7.7 lbs. (3.5 kg) versus 4.4 lbs. (2.0 kg) in the control group and there was a decrease in measured blood pressure.
An earlier study involved moderately obese women with borderline high blood pressure; they experienced a rapid reduction in blood pressure in the first 48 hours of fasting.9 Researchers have also found that short-term intermittent fasting reduced blood pressure taken in the office, but it did not affect central pressure or measurements taken at home.10
Research on fasting hasn't been limited to measuring only blood pressure changes. The authors of one study11 found that those who were obese benefited in several ways. A group of 110 people were hospitalized for three weeks for a fasting intervention.
They found, over the course of a three-week medically supervised fasting diet, that the participants experienced a reduction in blood pressure and lipids and an improvement in their glucoregulation, including insulin sensitivity.
Fasting Raises the Potential for Positive Change
Although there are some factors to living a long life that may be out of your control, the types of food you eat and the timing of your meals both play a significant role. Fasting may be one of the best ways to switch on your body's ability to promote cellular protection and regeneration.12
As it turns out, fasting may also reset your senses of smell and taste.13 Your sense of smell has an impact on food choices. Researchers found that rising levels of insulin reduced the sense of smell in participants and it changed how they experienced the taste of their food. This improved after a 24-hour fast.
Fasting has a positive impact on your gut microbiome. There's evidence your microbiome has an impact on your immune system, weight management and the development of chronic disease. Results from animal studies indicate that a life-long calorie restriction “significantly changes the overall structure of the gut microbiota” to help promote longevity.14 These changes:
“… reduced serum levels of lipopolysaccharide-binding protein, suggesting that animals under calorie restriction can establish a structurally balanced architecture of gut microbiota that may exert a health benefit to the host via reduction of antigen load from the gut.”
One chronic condition affected by fasting and by changes to your gut microbiome is Type 2 diabetes. The basis of the disease is insulin resistance, which is affected by fasting. Improving your insulin sensitivity15 helps your weight management efforts and helps reverse diabetes.16
Dementia is another health condition positively impacted by fasting and time-restricted eating. More than 5 million in the U.S. have Alzheimer's, just one type of dementia.17
It's important to remember there are simple steps that have a powerful impact on reducing these numbers, such as fasting that helps upregulate autophagy — the necessary process for optimal cell renewal and function. Discover more about how fasting affects cognitive function in “Time-Restricted Eating — A Powerful Way to Prevent Dementia.”
Impressive Metabolic Intervention Fraught With Myths
In this interview with Dr. Jason Fung you'll discover some of the benefits of fasting to your overall health. In his book “The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting,” he details how to implement a fasting program and overcome some of the challenges.
One of those challenges is unlearning the myths that have surrounded the practice. A common one is that you burn muscle when you fast. In his book, Fung clearly explains the process of protein catabolism and how the down-regulation of it and the up-upregulation of growth hormones in response to fasting does not lead to muscle loss. He says:
“What's interesting is that if you take a pound of fat, that's roughly 3,500 calories. If you eat somewhere around 1,800 to 2,000 calories a day, it takes two full days of fasting to burn a single pound of fat, which is very surprising to people.
If you're trying to lose 100 pounds, you could theoretically go 200 days of fasting just to burn all that fat … People worry about fasting for 24 hours. I'm like, ‘You could go 200 days.' Then it's like, ‘OK. Maybe it's OK to go 24 hours without eating.'”
The second common myth that may keep people from fasting is the belief their body will go into starvation mode and hold on to every calorie. However, this is the one effect that doesn't happen with fasting. Instead, it's an efficient way of accessing energy:
“What they're talking about is where the body's metabolism starts to slow down so significantly that instead of burning 2,000 calories a day, your body might burn 1,000 calories a day.
In that case, even if you're eating only 1,500 calories a day, for example, you're going to gain your weight back. That's actually what happens when you reduce your calories. We know that … as you cut your calorie intake, your calorie expenditure goes down as well.
Starvation mode actually is guaranteed if you just try and cut your calories. But what's interesting is that fasting doesn't do that. What happens during fasting is that … after four days of fasting, the basal metabolic rate is actually 10 percent higher than when you started.
The body has not shut down at all. In fact, what it's done is it switched fuel sources. It switched from burning food to burning [body] fat. Once it's burning [body] fat, it's like, ‘Hey, there's plenty of this stuff. Let's burn our 2,000 calories' …”
Insulin Plays a Crucial Role
The primary hormone your body uses to determine whether energy is stored or burned is insulin. Each time you eat your insulin levels go up, and the higher they go the more they tell your body to store energy. The reverse happens when insulin falls, it tells your body to release energy.
During insulin resistance your levels remain high and so your body is constantly storing fat. Now, without a signal to burn energy, you feel tired and sluggish. This is one reason it's so difficult to lose weight when you're insulin resistant.
To break this cycle, you have to sustain lower levels of insulin, and this is where fasting is beneficial. While fasting, your insulin levels lower and allow stored energy to be burned. Fung describes the surprise his patients express when they return to the office and tell him they're not really hungry while fasting.
The reason is because the body has turned to burning fat and doesn't need extra calories because it has enough. There's more to the story in a relationship between insulin resistance and high blood pressure.18 However, it has been a question of which came first, the chicken or the egg?
Researchers have been seeking an answer, and while they know the conditions happen together frequently, it's remained unclear which comes first.19 Thus, one pathway fasting may activate your body to lower your blood pressure is by reducing your insulin resistance.
Certain Foods Can Help Lower Blood Pressure
Fasting can help reduce your blood pressure, and so can the foods you eat. The quality of your health is directly impacted by what you feed your body. Since your blood pressure is not an isolated aspect of your health but rather tied closely to other functions of your body, it's important to pay attention to normalizing it.
There are foods you should steer clear of and those you should begin eating to help maintain normal blood pressure. It's worth noting that those living in the Mediterranean region have some of the healthiest, longest-living people in the world. The Mediterranean diet is known for rich olives and olive oil, fresh vegetables, fruits, seafood and, infrequently, red meat.
The diet is low in sugar with moderate amounts of protein; it is high in fresh fruits and vegetables and includes healthy fats. Dr. Stephen Sinatra promotes the Pan-Asian Modified Mediterranean (PAMM) diet which highlights avoiding “foods that contain sugar, refined white flour, partially hydrogenated oils, processed fruit juices, and omega-6 oils such as corn, safflower, soy, and canola.”20
KetoFasting, which combines a cyclical ketogenic diet and intermittent fasting with cyclical partial fasting is another way to optimize your health. My KetoFast protocol incorporates healthy fats that help with satiety and to accelerate autophagy.
Some foods that are heart healthy and tasty can easily be integrated into your daily routine. Arugula is high in potassium, magnesium and calcium; all of these are important for heart health. Pistachios, olive oil, tomatoes and celery are foods that help keep your arteries flexible and your blood pressure down. Discover more foods and why they're so helpful in my article, “Top Foods to Help Lower Blood Pressure.”
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