Fasting Has A Little-Known Effect On Your Blood Pressure

Alternate-day fasting, Eat Stop Eat, and time-restricted eating are just some of the trends in fasting that promise to cut those extra pounds. Some of these fasts allow you to drink water or vegetable broth on fasting days to keep calories at a bare minimum. Others might follow the 5:2 Diet and eat about 500 calories two days a week and eat as usual on the other five.

Fasting can help you lose weight because you're not only restricting your overall calories but also regulating the hormones that control your appetite. Besides, time-restricted eating can get you to think twice before you eat that unhealthy late-night snack. A 2021 article in Annual Reviews found that fasting can help you lose about 5% of your body weight on average. Fasting might also improve your cardiometabolic health. Although the types of fasting might vary, fasting overall can lower insulin resistance, oxidative stress, and blood pressure.

The combination of calorie restriction and fasting for 12 weeks can reduce your systolic blood pressure by 3.26 mm Hg and your diastolic blood pressure by 1.32 mm Hg, according to a 2020 review in High Blood Pressure & Cardiovascular Prevention. However, you don't need to be looking to lose weight to reap the blood pressure improvement from fasting. A 2021 study in the Journal of the American Heart Association studied people's blood pressure changes during Ramadan. During the 30 days of Ramadan, people don't eat or drink anything during daylight hours. On average, people's systolic blood pressure dropped by 7.29 mm Hg, and their diastolic dropped by 3.42 mm Hg.

Fasting might lower blood pressure through changes in your gut microbiome. A 2021 article in Nature Communications had people drink only vegetable juice or vegetable broth for five days before following a modified version of the Dietary Approaches to Stop Hypertension (DASH) diet. Compared to people who only followed the DASH diet, those who fasted had distinct changes in their gut microbiome that endured during the three months of the DASH diet. These changes in their gut bacteria were associated with lower blood pressure.

It might sound logical that your metabolic health would improve just by losing weight rather than fasting, but a 2018 article in Cell Metabolism found that time-restricted eating improves people's health without weight loss. For 5 weeks, men with prediabetes were asked to eat during a 6-hour window with dinner before 3 p.m. They ate enough food to maintain their weight. During another 5 weeks, they ate a similar diet but were allowed a 12-hour feeding window. When the men practiced eating during the restricted window, they improved their insulin sensitivity, blood pressure, and oxidative stress.

A typical American diet will have several spikes in blood glucose a day, and your body uses this glucose as its main source of energy. When you start intermittent fasting, you set off a metabolic switch in your body, according to a 2017 article in Obesity. Although everyone's bodies are different, this switch can occur between 12 and 36 hours after your last meal. As your body's glucose levels remain low for a while, your liver turns to your stored fat to produce ketones for energy. That's where you can see an improvement in your body composition and lower cholesterol. This metabolic switch also increases your insulin sensitivity while reducing inflammation and oxidative stress.