5 Things You Need to Know About Intermittent Fasting and Chronic Illness

Chronic fatigue. Muscle and joint pain. Gastrointestinal problems. Changes in weight. Headaches. Mood swings. Brain fog. All symptoms you may experience if you have a chronic illness, like rheumatoid arthritis, multiple sclerosis, or chronic kidney disease.

While most chronic illnesses don’t have a definitive cure, many experts agree that following an anti-inflammatory diet can help ease symptoms and even prevent a second chronic illness from developing.

A recent study found that pro-inflammatory diets increase the risk of 27 chronic diseases and premature death. This study reviewed 15 meta-analyses investigating the association between the Dietary Inflammatory Index (DDI) and 38 health outcomes from 4 million people all over the world. Researchers compared the health outcomes of people who follow a pro-inflammatory diet with those who follow an anti-inflammatory diet. They found that those who followed a pro-inflammatory diet were more likely to develop heart disease, certain cancers, some autoimmune diseases, and depression.

Following a diet that avoids inflammatory foods is one way to help reduce inflammation and improve health outcomes. But shifting the times you eat may help you feel even better. This type of eating plan, called intermittent fasting, has been shown to help reduce inflammation and even reverse some diseases.


What is Intermittent Fasting?

Intermittent fasting (IF)  is an eating plan that cycles between times of feeding (eating) and fasting. Instead of specifying certain foods to eat, it focuses on when to eat them.

There are several different ways to do intermittent fasting and are all based on choosing a regular time to eat and fast. Some common methods are:

  • The 16/8 method. This is the most popular method that involves fasting every day for 16 hours and eating during the remaining 8 hours. During this eating window, you can eat a few meals and a snack. Fasting for 16 hours every day can sound difficult, but it can be as simple as skipping dinner or breakfast, whichever fits your schedule best.
  • The 5:2 diet. This method requires normal eating for 5 days of the week and restricting calorie intake to a maximum of 600 calories for 2 days per week.
  • The 24-hour Fast. This style of IF is exactly how it sounds, fasting for a full 24-hour period. For example, if you eat dinner at 6 p.m. on Monday, you don’t eat again until 6 p.m. on Tuesday. You can also fast from breakfast to breakfast, or lunch to lunch. Water, black coffee, and other unsweetened, zero-calorie beverages are allowed during the fast.
  • Alternate-Day fasting. In this style of intermittent fasting, you fast every other day. Some variations of this type of IF allow for no more than 500 calories during fasting days. Because a full-day fast every other day can seem extreme, it’s not recommended for beginners or women. It may even result in some negative effects for those who struggle with chronic illness.

Adapting to a new eating schedule can be difficult at first. You may feel extra hungry, tired, or cranky at first, but should reside in a few days. If you notice other symptoms like dizziness, headaches, or nausea, talk with your doctor immediately.

How does Intermittent Fasting Impact Chronic Illness?


The human body has evolved to be able to go without food for several hours and up to a few days.  During this time of fasting, the body undergoes many different changes that have a profound effect on the body, like cell regeneration, reduction of inflammation, and improved cardiovascular function.

A systematic review investigated 13 primary and secondary research studies over the last 20 years to determine the impact of intermittent fasting and chronic disease in adults. Researchers evaluated biomarkers pertaining to inflammation, oxidative stress, and the cardiovascular system. They found that people who implement IF have a decrease in resting heart rate, blood pressure, blood LDL (bad cholesterol), and total cholesterol. They also found a decrease in inflammatory cells, oxidative stress, and an increase in insulin sensitivity.

While studies have shown several benefits of intermittent fasting, it may not be the best eating pattern for everyone. Here are some things you should know about how intermittent fasting impacts chronic illness.


1. Intermittent Fasting Helps with Weight Management

Obesity or overweightness is a chronic condition associated with poorer mental and physical health outcomes, and quality of life. Studies show that people who are obese or overweight are at a higher risk for developing other chronic conditions like heart disease, stroke, type 2 diabetes, some types of arthritis, and certain cancers.  Researchers believe obesity and chronic disease are connected by inflammation in the body. Obesity creates a pro-inflammatory environment that can cause a progression of the disease and interfere with treatment, like medication or physical activity.

For people who struggle with more traditional, calorie-restrictive diets as an approach to weight loss and weight management, IF may be a better option. A 2021 review published in the Annual Review of Nutrition found that intermittent fasting leads to roughly the same amount of weight loss compared to traditional calorie-restrictive diets. The study looked at the impact of all forms of fasting, like alternate day fasting and time-restricted eating, on weight loss. One of the primary findings of the study was that people who followed intermittent fasting lost about the same amount of weight as those who cut 500 calories per day.

By reducing and managing weight and putting your body in a healthy, anti-inflammatory state, you can help reduce your risk of developing chronic diseases. If you already have a chronic disease, weight management can help slow the progression of the disease and ease symptoms.


2. Intermittent Fasting Can Reduce Inflammation

Inflammation occurs when the body activates the immune system in response to trauma, like an injury or illness. When the immune system is activated, it releases inflammatory cells and cytokines. These cells trap bacteria to heal the injured tissue. But, when the body continues to send inflammatory cells once the trauma has passed, it can lead to chronic inflammation which in return, can result in chronic illness. Some chronic conditions associated with chronic inflammation include:

  • Cancer
  • Heart disease
  • Rheumatoid Arthritis
  • Chronic Kidney disease
  • Type 2 diabetes
  • Multiple sclerosis

Research has shown that fasting reduces inflammation and in return, improves chronic inflammatory diseases. One study performed by Mount Sinai found that in both human and mouse immune cells, intermittent fasting reduced the release of pro-inflammatory cells into the blood, called monocytes. Monocytes are a highly inflammatory immune cell that destroys germs and eliminate infected cells. But too many monocytes and under the wrong circumstances, like when there aren’t any infected cells, causes severe tissue damage.  The study found after a short-term fast of just 4 hours there was a slight decrease in monocytes. After 20 hours of fasting, they saw a significant decrease in monocytes circulating in the blood.

Another study found that people who fasted for a 24-hour period once a week had increased levels of galectin-3, compared to those who didn’t not fast. Galectin-3 is a cellular-repair protein that has been tied to easing inflammation. The study examined 67 participants between the ages of 21 and 70, and all had at least one metabolic syndrome feature of type 3 diabetes. Half of the participants followed a twice-a-week 24 hour fast for four weeks, followed by a once-a-week 24 hour fast for the remaining 22 weeks. The other half of the participants made no changes to their diet or lifestyle. After 26 weeks, researchers found higher levels of galectin-3, lower rates of insulin resistance, and decreased symptoms of metabolic syndrome in participants who fasted compared to those who didn’t.


3. Can Improve Heart and Blood sugar Markers

A well-researched benefit of intermittent fasting is the positive effect on heart and blood sugar markers. An umbrella review of analyses that examined the impact of different IF regimens on metabolic and cardiovascular health found that people who fasted saw improvements in blood sugar levels, blood pressure, insulin sensitivity, and cholesterol levels, all of which are risk factors for heart disease.

The study reviewed 11 meta-analyses of 130 clinical trials. The data revealed that modified alternate-day fasting and 5:2 fasting had greater associations with a reduction in fasting insulin levels. Other studies found that IF can improve regulation of blood sugar, increase resistance to stress, and suppress inflammation.

When you have conditions like diabetes or heart disease or have risk factors for them, you also increase the risk of developing other chronic conditions like rheumatoid arthritis (RA) and depression. Studies show that people who have RA are twice as likely to develop heart disease, and vice versa.

Other studies have shown there is a two-way relationship between heart disease and depression, that having either one can lead to the other. A heart attack, stroke, or arrhythmias impact a person’s heart as well as:

  • Attitude and mood
  • Sense of certainty
  • Self-confidence
  • Feelings of guilty over the cause of heart condition

When these feelings and beliefs become overwhelming, they can interfere with daily functions and lead to a depressive episode.

If you have a heart condition or risk factors, it’s important to talk to your doctor about ways to protect your heart so you can decrease the likelihood of developing other chronic conditions.


4. May Increase or Cause Other Symptoms

Intermittent fasting is safe for most people. However, if you already experience symptoms like headaches, fatigue, dizziness, and anxiety, it could make them worse.

When you reduce calories too much or go too long without any food, blood sugar levels will drop. This is called hypoglycemia. Some signs of hypoglycemia include:

  • Dizziness
  • Shaking
  • Rapid heart rate
  • Irritability and anxiety
  • Mood swings
  • Difficulty concentrating

Many times, blood sugar drops without people noticing, making it a dangerous condition. Once you feel any symptoms of low blood sugar, it’s important to seek treatment immediately, If blood sugar drops too low for too long, you may faint, have a seizure or even go into a coma in extreme circumstances.

Hypoglycemia is very common in people with diabetes because of the lack of or too much insulin introduced into the body. Insulin is a hormone that breaks down sugar to be used for energy. Too much insulin can cause the body to break down sugar too fast, resulting in low blood sugar. But abnormal blood sugar levels, whether too low or too high, can impact other chronic conditions like heart disease, Parkinson’s disease, multiple sclerosis, and fibromyalgia.

One research study found that Parkinson’s patients who had too low or too high blood sugar levels experienced increased levels of cognitive impairment, compared to those who had normal blood sugar levels. Another study found that MS patients are at higher risk of fasting hypoglycemia and orthostatic hypotension, or abnormal blood pressure, compared to the general population.


5. Intermittent Fasting Can be Dangerous with Certain Medications

If you have a chronic illness, you are likely taking at least one type of medication to help manage and reduce symptoms. With conditions like multiple sclerosis and rheumatoid arthritis, you may even be taking disease-modifying drugs to slow the progression of your condition.

Some medications need to be taken with meals for them to be absorbed into the bloodstream properly. Other medications, like non-steroidal anti-inflammatory drugs (NSAIDs) and steroids, may cause upset stomach or nausea if taken without food.

Skipping meals or severely lowering calorie intake can be dangerous for people with conditions like diabetes and heart disease. People who take medications to manage these conditions are more prone to imbalances of sodium, potassium, and other minerals, during long periods of fasting, which can lead to dizzy spells and fainting.

Is Intermittent Fasting Right for You?

Everyone responds to diets differently. What works best for one person, may not work well for you. Studies show that women tend to experience negative effects after 16 hours of fasting because their bodies are more sensitive to stressors, like fasting itself. Prolonged calorie restriction can lead to elevated cortisol, loss of menstrual cycle, and disorder eating.

When deciding if intermittent fasting is right for you and what type of IF you want to try, it’s important to consult your health care provider. If you have a chronic illness, it doesn’t mean you can’t fast, but there may be certain precautions you need to take to fast safely and prevent any negative side effects that may exacerbate your condition.

If you are considering intermittent fasting to help manage your condition, connect with others who know what you are going through. At PatientsLikeMe, there are thousands of members who are using different dietary methods to help manage their illnesses. Join the conversation day.

Please follow and like us:
Scroll to Top