Intermittent Fasting by Age Chart: A Guide on How it Works

July 9, 2024
March 14, 2024
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In case you don’t already know, there has been a diet trend that has been going around for quite some time. This diet trend is called ‘Intermittent Fasting (IF)’ and most people have tried it at some point.

You see people talking about what it is and vlogging their experiences on social media platforms like Instagram, TikTok, and more. The impact of this diet can be seen across the different age groups with individuals actively striving to transform their lifestyles.

So, what exactly is the fuss about intermittent fasting with people of all ages? In this guide, we will try to unpack this together.

Understanding How Intermittent Fasting Works

Intermittent fasting is a weight loss approach that practices restricting eating and drinking to specific times of the day. There is a structured fasting and eating window that you must follow in order to reap the benefits.

To put it simply, intermittent fasting works by making your body go through extended periods of time without food. In doing so, it allows your body to tap into stored energy reserves and undergo different metabolic processes. During this period, the body goes into a state known as ketosis, which is known to be beneficial for the body [2].

The Influence of Age on Intermittent Fasting

As we start to age, our bodies are bound to change. We will not respond to various lifestyle changes the same way that we did, some years ago. This includes intermittent fasting.

As we go through the different stages of our lives, our metabolism, hormones, and overall health needs will evolve. Thus, this will affect the experience and benefits that we receive from fasting. These are some age-related factors to consider and understand before starting intermittent fasting.

Metabolic Changes

Age can affect our metabolism. When we age and we do not practice taking care of our health, our metabolism slows down. Young adults tend to have faster metabolism in comparison to older adults, thus making it easier for them to adapt to intermittent fasting. They may also potentially witness a faster change in terms of weight loss.

Hormonal Changes

Hormones play an important role when it comes to regulating appetite, energy expenditure, and fat metabolism. As we age, our growth hormone and insulin sensitivity decline. This means that if intermittent fasting is done, there may need to be modifications to the fasting schedules so as to see better results.

Health Conditions & Medications

Especially for older adults, the risk of chronic health conditions such as high blood pressure, diabetes, heart disease, and osteoporosis increases. Most of the time, it would require medications in order to manage the various conditions.

Certain health conditions and medications may influence the safety and effectiveness of intermittent fasting. Thus, such people would need to consult with their healthcare professionals and make proper considerations before implementing intermittent fasting plans into their routine [3].

Intermittent Fasting Chart by Age

When it comes to deciding on a suitable plan, there is a need to consider different factors such as age, current activity levels, lifestyle, and nutrition. To help you decide on what is the best plan for you based on your age, we have created an intermittent fasting plan based on the age chart for your reference below:

For those aged 18-30

intermittent fasting chart by age

Individuals in this age group generally have higher energy levels and are more inclined to engage in social activities like having a night out with friends, eating out with the family, or drinking with colleagues.

Based on lifestyle, you could opt for a more flexible schedule such as the 16:8 method where the fasting window is 16 hours and the eating window is 8 hours.

For those aged 30-45

Usually, those in this age group tend to have more responsibilities and a tighter everyday schedule. Having to take care of children, doing household chores, and managing existing work commitments can get overwhelming.

Thus, it may be worth considering adopting a schedule that is easy to maintain like the 16:8 or 14:10 method. Alternatively, if you need a longer eating window for whatever reason, you may also opt to do the 14/10 method.

For those aged 45-60

At this age, metabolism would have started to slow down leading to increased weight gain. For women, they would also start to experience hormone fluctuations at this stage from menopause. It may be beneficial for those in this age group to try sticking to a longer fasting window by following the 18:6 method (18 hours fasting, 6-hour eating window).

Throughout this fasting period, it is also important to focus on nutrition and eat healthily.

For those aged 60 and above

Older adults in this age group should adjust their fasting schedule according to their nutritional needs. These individuals have the risks of potential vitamin deficiencies and higher difficulty in meeting their daily nutritional needs.

Shorter fasts like 12:12 or 14:10 may be suitable for this age group in this case. With longer eating windows, they will have plenty of time to eat and meet their daily goals. It is extremely important to consult with a healthcare professional before going on this diet.

A healthcare professional with be able to give proper advice with regard to fasting and assess whether individuals have any underlying health conditions that may directly affect fasting.

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Intermittent Fasting Schedule

Once you have determined the appropriate fasting plan to follow, you then want to create a fasting schedule to follow. Here’s an example of an intermittent fasting schedule:

intermittent fasting schedule

Do take note that you do not have to follow this exactly. You may adjust fasting periods and timings based on what you are most comfortable with. This only serves as a guide to help you get started on your fast.

Benefits of Intermittent Fasting Across Different Age Groups

fasting for dinner 
intermittent fasting

There are many health benefits when it comes to implementing intermittent fasting as part of your lifestyle. The benefits range from physical improvements like better body composition to cognitive improvements like better brain function. Notable advantages include:

1. Weight Loss

One of the main benefits of intermittent fasting is weight loss. Generally, it helps to reduce the amount of meals that you are eating because of a strict eating window period to follow. This means a lowered calorie intake.

Studies have also been done to see if intermittent fasting can work as an alternative to calorie restriction and help participants lose weight. Across all intermittent fasting trials, it was observed that overweight and obese patients experienced weight loss ranging from 0.8% to 13.0% of their baseline weight, with no significant adverse effects reported [5].

2. Reduces Risk of Type 2 Diabetes

Intermittent fasting has been shown to help reverse insulin resistance and reduce blood sugar levels. A reduced blood sugar level helps to reduce the risk of type 2 diabetes.

A study was done in 2018 with the use of Early Time-Restricted Feeding (eTRF), a form of intermittent fasting, for 5 weeks. The study concluded that eTRF improved insulin sensitivity, signifying the positive efficacy of intermittent fasting.

3. Reduces Risk of Heart Disease

Intermittent fasting can help to improve several risk factors for heart disease such as blood sugar levels, blood pressure, total and LDL (bad cholesterol).

4. Prevents Alzheimer’s Disease

Based on observations in a 2023 review, it was concluded that intermittent fasting could potentially reverse the effects of Alzheimer’s Disease or at least delay the onset of it.

However, there may be more research needed in the future to confirm that it is a benefit of intermittent fasting.

Who Should Avoid Intermittent Fasting?

who should avoid intermittent fasting

Intermittent fasting (IF) may not be suitable for everyone, and certain individuals should exercise caution or avoid it altogether. Here are some groups who should consider avoiding intermittent fasting:

  • Individuals with diagnosed eating disorders
  • Children or adolescents
  • Pregnant or breastfeeding women
  • Individuals with pre-existing medical conditions
  • Individuals with a history of adverse reactions

Tips for Successful Implementation

helpful tips for successful implementation

To successfully implement intermittent fasting into your lifestyle, you have to establish a goal that you want to achieve with this diet. Not just that, but it is also about practicing mindfulness when approaching this diet. Here are some tips that will set you up for success:

  • Start slowly: When implementing a new diet, it is important to not rush into it and slowly ease yourself into it. For example, you could start off with fasting for a few hours and gradually increase it. Doing so will encourage you to stick to the fasting regimen.
  • Choose the right method: Do not feel pressured to pick a method that is challenging or follows exactly the chart or schedule above. Always choose something that aligns with your goals and lifestyle. This way, you won’t be tempted to give up on making positive changes easily.
  • Stay hydrated: Just like it is in daily life, always keep yourself hydrated. Drinking plenty of water can help you curb your hunger and make you feel fuller for longer.
  • Listen to your body: Pay attention to how you feel throughout the day. Notice your energy level, hunger cues, and your well-being. If at any point you notice yourself feeling unwell, it is best to stop and adjust the plan accordingly.
  • Consult a professional: If you are just starting out or you have pre-existing medical conditions, you are strongly advised to consult a health professional. This is to ensure that you are suited for the diet.

Age-Related Considerations

Especially for seniors aged above 60, it is best to start out slow and gradually work up to intermittent fasting and to consult a health professional for more advice. Some of the potential risks that seniors could face while on this diet are:

  • Increased fall risk
  • Possible vitamin deficiencies
  • Lowered metabolic rate

Navigating Intermittent Fasting For Well-being

To sum up, if you do decide to start intermittent fasting, you should consider choosing a schedule that best suits you based on your lifestyle and understanding what is appropriate for your age. Take breaks whenever needed and always practice proper self-care and self-kindness. All the best on your intermittent fasting journey!

Other Diet Resources

If you liked this article, make sure to check out these articles on our JustFit Blog:

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Elias, A., Padinjakara, N., and Lautenschlager, N. T. (2023) Effects of intermittent fasting on cognitive health and Alzheimer's disease. Nutrition reviews, 81(9), 1225–1233.

Harvard Health Publishing (2023) Time to try intermittent fasting? [online]. Available at:

Harvard Health Publishing (2020) Is intermittent fasting safe for older adults? [online]. Available at:

Sutton, E. F., Beyl, R., Early, K. S., Cefalu, W. T., Ravussin, E., and Peterson, C. M. (2018). Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell metabolism, 27(6), 1212–1221.e3.

Welton, S., Minty, R., O'Driscoll, T., Willms, H., Poirier, D., Madden, S., and Kelly, L. (2020) Intermittent fasting and weight loss: Systematic review. Canadian family physician Medecin de famille canadien, 66(2), 117–125.

About authors
Siti Amirah
Written by
Amirah is a dedicated content writer with a deep passion for mental health and wellness. Recently, she has expanded her focus to include fitness and overall health, motivated by her commitment to cultivating a healthier lifestyle. She hopes to provide valuable insights and tips for others to lead a healthy and fulfilling life.