Intermittent Fasting for Seniors: Risks, Benefits, and More

This article was written by University of Alabama dietetic student Rachael Switliski with review and edits by Katie Dodd, MS, RDN, CSG, LD, FAND.

Disclaimer: Intermittent fasting may not be appropriate for everyone, particularly older adults with certain medical conditions, those taking medications, or those at risk for unintended weight loss or malnutrition. Always consult your healthcare provider before starting intermittent fasting. This article is for educational purposes only and is not intended to replace individualized medical advice.

Let’s face it. It’s difficult to research intermittent fasting. A quick Google search leads you down a rabbit hole of social media posts, articles, scientific journals, and blog posts (which is why you’re here, hi).

There’s lots of contradicting information that leaves you more confused than when you started. Allow me to break it down for you.

This article will cover what intermittent fasting is, reasons why people do it, types of intermittent fasting, potential benefits, potential risks, and why it may be different for seniors. Let’s get started.

What is Intermittent Fasting?

Intermittent fasting is an eating pattern that alternates between periods of eating and fasting. There are several approaches, including limiting eating to certain hours of the day or reducing calorie intake on specific days of the week.

So, what is the difference between fasting and intermittent fasting? Fasting simply means going without food for a period of time. Intermittent fasting, on the other hand, involves following a repeated pattern of fasting and eating.

Simply put, intermittent fasting is relatively short and maintains a consistent schedule.

For instance, a person may complete a five-day fast where they consume nothing but water for religious reasons. This would not be considered intermittent fasting.

There are many different types of intermittent fasting, including time-restricted, day-based fasting, modified fasting, and periodic fasting.¹

Intermittent fasting can also be done for a variety of reasons. Some may do it for one reason or multiple.

Quick aside, but periodic fasting isn’t always considered intermittent fasting. More on that later.

Why Do People Intermittent Fast?

People practice intermittent fasting for a variety of reasons, including religious beliefs, potential health benefits, and personal or emotional goals. Some people may fast for one reason, while others may have multiple motivations.

Religious reasons

One example of intermittent fasting for religious reasons is found in the Islamic religion. Healthy Muslims fast from dawn to sunset during the month of Ramadan. During this fasting period, they do not consume food, beverages, or engage in certain activities, such as smoking cigarettes. The length of the fast from dawn to sunset varies depending on a person’s location and the time of year.

Seventh-day Adventists also practice fasting for religious purposes. They consider a healthy diet and lifestyle to be expressions of their faith. One study found that many Seven-day Adventists consume only two meals a day in the afternoon, which leads to a prolonged nightly fast.²

Fasting is practiced by followers of many religions, including Christians, Hindus, Buddhists, Jews, and Jains. However, these fasting practices vary.³

Health Reasons

Some commonly cited reasons why people practice intermittent fasting include the following. However, the strength of evidence varies, and many of these potential benefits have not been established in older adults.

• Improved blood sugar
• Weight loss
• Healthier cholesterol
• Lower blood pressure
• Reduce inflammation
• Increased lifespan
• Increased immunity
• Lower risk of diabetes
• Lower risk of cardiovascular disease
• Improved cognition (brain functioning)

Emotional Reasons

For some, intermittent fasting may be a way to become more disciplined by being more intentional about their food habits, setting boundaries around eating, and managing emotional eating.⁴

While people may practice intermittent fasting for different reasons, it’s important to understand that not all of its potential health benefits are supported by strong scientific evidence. Intermittent fasting also comes with potential risks, particularly for older adults.

Types of Intermittent Fasting

There are several different types of intermittent fasting, and not everyone follows the same approach. Some methods involve limiting the hours of the day when food is consumed, while others involve restricting calories on certain days of the week.

Understanding these differences is important because the potential benefits and risks may vary depending on the type of fasting practiced.

Time-restricted Fasting

Time-restricted eating involves consuming food within a designated number of hours each day and fasting during the remaining hours.

We all naturally fast when we sleep. Time-restricted fasting is fasting with intention. Consider the 24 hours in a day. With the 24-hour cycle, the fasting window is often longer than their eating window. The eating window is typically between 6 to 10 hours, although it can be longer or shorter.¹

The pattern here is hours fasting: hours eating. So, someone following a 16:8 fast will not consume food for 16 hours and will need to consume their calories within 8 hours every day.

Notice that these numbers are based on a 24-hour day, and thus always equal 24!

Day-Based Fasting

If someone fasts based on days of the week, they will restrict all or most of their calories. On the days they fast, they will eat 25% of their recommended calories at most. This is based on a schedule. Here are some examples.

• Alternate-day fasting means fasting every other day. This would look like eating on Sunday, fasting on Monday, eating on Tuesday, and so forth. On the days the person doesn’t fast, they would follow a normal eating pattern. However, on their fasting days, they may eat between 0 and 25% of their required calories.

If you’re confused by required calories, I’ll explain below the next table.

• 5:2 means eating normally for 5 days of the week and fasting for the other two days of the week. However, the fasting days are not back-to-back. This may look like fasting on Tuesday and Friday and eating normally the other days. Unlike alternate-day fasting, the person does freely not eat as much as they want. They follow a normal eating pattern.

5:2 isn’t to be confused with the order of time-restricted fasting, where the ratio is fasting hours: eating hours. The ratio for day-based fasting here is days eating normally: days fasting.

• Other patterns of day-based fasting are fasting 1 or 4 days of the week. This would mean consuming 0-25% of required calories for those days and eating normally the other days.¹

Estimated calorie needs refer to the amount of energy a person requires each day to maintain their current weight, based on factors such as age, sex, height, weight, and physical activity.⁵

Thus, if someone required 2,000 calories a day, then they would consume between 0 and 500 calories a day when following day-based fasting.

What are the Potential Health Benefits?

We discussed some of the reasons earlier that people may intermittently fast for many reasons, including religious, mental, or health.

But what does the science say about the potential health benefits? It’s important to recognize that the science is still evolving. Thus, the health benefits are possible but not yet proven.

Let’s dive into what the research is currently saying about some of these potential health benefits.

Improved blood sugar

A 2026 systematic review examined 31 studies on intermittent fasting in adults aged 60 and older. Some studies found improvements in blood sugar management, including HbA1c, although more research is needed.⁶ HbA1c is a blood test that evaluates blood sugar control over the past three months.

A different metanalysis evaluated 4 studies on intermittent fasting in overweight or obese patients with type 2 diabetes and metabolic syndrome. It concluded that intermittent fasting could be used in patients with type 2 diabetes while recognizing that further studies with more people are needed to ensure the effectiveness and safety in this population.

However, this metanalysis did not focus on older adults. Thus, it may not apply to that population. More research is needed to ensure it is effective and safe for them.⁷

If you’d like to learn more about diabetes in older adults, you can read more about it here: https://thegeriatricdietitian.com/diabetes-in-the-elderly/.

Weight loss

A 2026 systematic review and meta-analysis found that certain intermittent fasting approaches, including 16:8 time-restricted eating, were associated with weight loss in older adults without significant loss of lean mass in the included studies. However, maintaining muscle mass is especially important with aging, and additional research is needed to understand the long-term effects.⁶

This is so important because sarcopenia, or muscle wasting, increases with age. Sarcopenia leads to older adults becoming weak and unable to live independently.

However, this weight loss isn’t specific to intermittent fasting. If someone follows a 16:8 fast and has an 8-hour window to eat, they tend to naturally eat less calories compared to someone who might have a 14-hour eating window. In other words, intermittent fasting produces the same weight loss results as someone restricting their calories.⁸

Healthier cholesterol

The studies on this one are unclear. First, let’s talk about cholesterol.

• HDL is good cholesterol. This one removes excess bad cholesterol.
• LDL is bad cholesterol. This cholesterol forms plaque in your arteries. This is the cholesterol people talk about lowering.
• Total cholesterol includes HDL, LDL, and cholesterol carried by other lipoproteins.
• Triglycerides are a type of fat found in the blood. High triglyceride levels are associated with an increased risk of cardiovascular disease.

Research on intermittent fasting and cholesterol in older adults has shown mixed results. Some studies have reported improvements in cholesterol levels, while others have found little benefit or unfavorable changes. More research is needed to understand these effects.⁶

Lower blood pressure

Some studies suggest that intermittent fasting may help reduce systolic blood pressure (the top number) and diastolic blood pressure (the bottom number) in adults aged 60 and older.⁶ High blood pressure can refer to either or both numbers being too high.

Reduce inflammation

Some studies involving adults aged 60 and older have found improvements in markers of inflammation among people who practiced intermittent fasting. However, more research is needed to determine whether these findings translate into meaningful long-term health benefits.⁶

Increased lifespan

A 2026 study has recently been cited to demonstrate how fasting can make humans live longer.¹⁰ The study not only included intermittent fasting, but other forms of fasting as well. While the study did not focus on intermittent fasting, it has been cited to say that intermittent fasting makes you live longer.

It is important to differentiate fasting forms to understand the effects, Additionally, this study was performed in worms and has yet to be replicated in humans.

There have been numerous studies demonstrating an increase in lifespan in other organisms, including yeast, bacteria, and mice. Although findings from animal studies are promising, there is currently insufficient evidence to conclude that intermittent fasting increases lifespan in humans.

According to the American Heart Association, a study on 20,000 people showed that “time-restricted eating did not reduce the overall risk of death from any cause.”¹²

This may demonstrate that the long-term effects of intermittent fasting, such as its effect on longevity, is unknown in humans.

Increased immunity

Three promising studies suggest that calorie restriction via intermittent fasting can redistribute white blood cells into bone marrow, which may affect immune function. However, these studies reveal that different forms and lengths of fasting produce not only different, but sometimes opposite effects.

Thus, the effects on immunity depend greatly on the type and duration of fasting. More research is needed to understand whether these changes actually improve immunity, especially in older adults.¹³

Lower risk of diabetes

Intermittent fasting can improve glucose profiles and can potentially lower the risk of chronic diseases, such as diabetes.¹⁴ However, more research is needed to determine whether it reduces the risk of developing type 2 diabetes, particularly in older adults.

Lower risk of cardiovascular disease

A systematic review and metanalysis using 56 different studies demonstrated that intermittent fasting, particularly modified alternate-day fasting and time-restricted eating, lowered cardiovascular risk factors. Intermittent fasting reduced body weight, LDL levels, blood pressure, fasting blood sugar, and waist circumference.

 However, improvements in these risk factors do not necessarily mean that intermittent fasting prevents cardiovascular disease. Additionally, rhe average age of the participants was 45 years old. Thus, the study was not done in older adults.¹⁵

Improved cognition (brain functioning)

Intermittent fasting shows increased cognitive functioning in mice,¹⁶⁻¹⁷ but the studies on humans are limited.

A systematic review and metanalysis on adults aged 60 and older found that long-term structured intermittent fasting improved cognitive performance, which was evaluated using methods proven to be valid. However, eating windows of ten hours or less led to lower cognitive scores.⁶

More research is needed before recommending intermittent fasting to improve cognitive health.

What are the Potential Health Risks?

While intermittent fasting may offer some health benefits, it also comes with potential risks. This is especially important for older adults, who may have additional health concerns or nutritional needs.

Let’s take a closer look at some of the potential risks of intermittent fasting.

Low blood sugar

Intermittent fasting may improve insulin sensitivity in type II diabetic patients.⁷

Insulin is the hormone that allows glucose (blood sugar) to enter your cells. Without enough insulin or without insulin sensitivity, glucose can’t enter your cells, which causes high blood sugar (hyperglycemia). 

Higher insulin sensitivity means that less insulin is needed to make blood sugar enter your cells, thus less high blood sugar!

However, low blood sugar (hypoglycemia) is also a concern. Going long periods without food may increase the risk of hypoglycemia, especially for people taking insulin or certain diabetes medications, such as sulfonylureas.

It is important to speak with your healthcare provider before making changes to your eating schedule or diabetes medications.

Intermittent fasting can pose significant risks for people with type 1 diabetes and should not be attempted without individualized medical guidance and close monitoring.¹⁸

Nutrient Deficiencies

When you have a short window to eat, you tend to eat less calories. The less calories a person eats, the higher the risk they are of nutrient deficiencies. It can be difficult to get the nutrients needed, especially if appetite is poor, which is a common complaint of older adults.  

Older adults are especially at risk for nutrient deficiencies. Certain nutrient needs change with age, and adequate protein intake is especially important for preserving muscle mass. Careful meal planning can help older adults meet their calorie, protein, and other nutrient needs.

Cardiovascular Disease

Some observational research has raised concerns about the potential cardiovascular risks of prolonged fasting.

Preliminary research presented at an American Heart Association scientific meeting in 2024 examined data from more than 20,000 adults. Researchers found that people who consumed food within an eating window of fewer than 8 hours per day had a 91% higher relative risk of cardiovascular death compared to those who ate within a 12- to 16-hour window.

However, this study was observational and does not establish that intermittent fasting caused the increased risk. Other factors, including underlying health conditions and overall dietary intake, may have influenced the results.¹²

More research is needed to better understand the long-term cardiovascular safety of intermittent fasting.

A 2026 systematic review involving older adults also identified observational research associating overnight fasting periods longer than approximately 12.4 hours with a 58% higher relative risk of cardiovascular death compared with intermediate fasting durations. However, these findings do not establish that fasting caused the increased risk.⁶

When taken together, these studies demonstrate that the long-term effects of fasting are not well understood.

Risk of Muscle Loss and Malnutrition

Weight loss can be particularly concerning in older adults, especially when it is unintentional or accompanied by muscle loss.

As we age, we naturally lose muscle mass and strength. This makes it especially important for older adults to preserve the muscle they have. Muscle loss can increase the risk of weakness, falls, and loss of independence.

Intermittent fasting may make it more difficult for older adults to consume enough calories and protein, especially if they already struggle with poor appetite or unintended weight loss. Over time, inadequate nutrition can increase the risk of malnutrition and further muscle loss.

If you are an older adult experiencing unintended weight loss, it is important to speak with your doctor and consider working with a registered dietitian to ensure you are meeting your nutritional needs.

Why is Intermittent Fasting for Seniors Different?

Older adults often have issues with poor appetite. They may get full fast, which can make eating all their meals in a short window difficult.

Some older adults experience changes in digestion and nutrient absorption, which can affect their nutritional status. Additionally, certain nutrient needs change with age. A shorter eating window may make it more difficult to meet calorie, protein, and other nutrient needs.¹⁹

If not done carefully, intermittent fasting can cause nutrient deficiencies, unneeded weight loss, and muscle loss.

With the food-related difficulties seniors experience such as poor appetite and reduced nutrient absorption, intermittent fasting may not be the best fit. However, it is important to consider a personalized approach.

Overall, the studies on intermittent fasting focus on adults, not older adults. More studies are needed to understand the effects on this population, especially long-term. Thus, much of the information known about intermittent fasting may not apply to this population.

The current research suggests possible positive short-term health benefits for older adults, such as increased insulin sensitivity.

If you decide to do intermittent fasting, it is vital to prevent unintended weight loss and to protect muscle health. If unintended weight loss is a persisting problem for you or an older adult in your life, you may want to consider seeing a geriatric dietitian.

Starting Intermittent Fasting for Seniors

If you’re an older adult considering intermittent fasting, it’s important to consider your individual nutritional needs and health circumstances before getting started.

1. Talk with your healthcare provider. This is especially important if you have diabetes, take medications, or have a history of unintended weight loss.
2. Prioritize adequate nutrition. Plan meals that provide enough calories, protein, and essential nutrients to help maintain your health and muscle mass.
3. Avoid overly restrictive eating windows. Make sure you have enough time to eat regular meals and meet your nutritional needs.
4. Monitor your health. Pay attention to changes in weight, energy levels, appetite, and blood sugar or blood pressure when appropriate.
5. Consider working with a registered dietitian. A dietitian can help determine whether intermittent fasting is appropriate for your nutritional needs and health goals.

Conclusion

The evidence on intermittent fasting is continuously emerging and shows promising results. However, older adults have special considerations that warrant caution. There may be various health benefits of intermittent fasting, but many studies have been conducted in animals or younger populations.

It is important to consider personal health circumstances before beginning intermittent fasting. Older adults have unique nutritional needs, and intermittent fasting may increase the risk of inadequate nutrient intake, unintended weight loss, and muscle loss.

More research is needed to understand the long-term safety of intermittent fasting in older adults. If you are considering intermittent fasting, speak with your healthcare provider or a registered dietitian to determine if it is appropriate for you.

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