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  • Writer's pictureSandhya Gokal

Intermittent fasting by age


Intermittent fasting is an eating pattern that focuses on when you eat rather than what you eat. Intermittent fasting has been studied as a beneficial strategy for weight loss, and to improve health measures like blood glucose, heart health, immune health and inflammation.


In my previous post on intermittent fasting, I explored the different time plans used in intermittent fasting, its risks and the benefits that could be gained. If you are new to intermittent fasting, I suggest you read that one first, so you have an understanding of the basic principles and rules to guide you on your intermittent fasting journey.


Today let’s explore if there is any intermittent fasting schedule that works for particular age groups. 



As always, I use my knowledge as a pharmacist, scientific based evidence and a healthy dose of imagination to venture into the topic being covered. So grab your explorer's hat, take a big gulp of water and off we go - to the land of intermittent fasting by age!


Why should I change my intermittent fasting plan based on age?


As you age, your body has different nutritional needs. For example, a young 20-something student has very different needs from a late 30’s person in a sedentary job - the energy requirements to fuel the body and your daily activities would differ. 


This means if you are in your…


20-30’s: intermittent fasting can help you maintain a healthy weight, and prevent chronic lifestyle disease in the future such as heart disease and type 2 diabetes. 


40’s and 50’s: intermittent fasting can help support cognitive function, improve energy levels needed to juggle life’s commitments and maintain a healthy weight


60’s and beyond: In this stage of life, you might be struggling with declining health and the ability to maintain a healthy weight given the reduced mobility. Intermittent fasting can be a great strategy to improve heart health and improve cognitive function. 


What does the research show about intermittent fasting in older adults?


Interestingly, not a lot of research has been done to show that one intermittent fasting plan is better than another for different age groups! (2). 


A 2021 study stated showed in the middle aged and elderly group, there is some evidence showing that fasting results in better blood pressure control but more studies need to be done on a larger scale to confirm these results. 


As early as 2013, there was a study showing empirical evidence that when older adults did a modified fast under medical supervision, they showed improvements in rheumatic disease, chronic pain and blood pressure! Cool right? So fasting has medically proven benefits for people with chronic conditions. 


Another consideration is that older adults who take medication which needs to be taken alongside food for better absorption might find intermittent fasting affecting the effectiveness of their medications. 


Looking at the differing energy and nutritional needs for different stages of life can be a good way to determine which schedule might work best. Some say looking at the values per age group can play a part - the social needs at a particular stage of life, or work-life balance, or even just the amount of time awake vs asleep. 


For example, a uni student would need an intermittent fasting plan that factors in a vivid social life so doing a flexible intermittent fasting plan would be much more effective and prevent a feeling of failure. 


On the other hand, a business person with a regular schedule might fare much better on a rigid structure that takes into account waking and work hours. 


By taking your lifestyle and making sure your intermittent fasting plan fits in snugly, you are much more likely to succeed and make a long term healthy eating habit that can be maintained with minimal effort. 


So once you take into account your age, the next question you might ponder is….is there anyone who SHOULDN’T try intermittent fasting?


Who shouldn’t try intermittent fasting, no matter what age




Since there’s not a huge amount of research on whether or not using age as a determining factor for your intermittent fasting plan is effective, most people can safely use intermittent fasting as long as it fits into your lifestyle.


However, there are some groups of people who should not participate in intermittent fasting no matter what age group they fall into. 


Pregnant women


Pregnancy is a time where nutritional needs go up to make sure that both mother and baby are getting enough nutrients. This usually means increasing food intake, a feat that can be hindered by things like nausea, gestational diabetes and food aversions. Because of this, intermittent fasting is not recommended for pregnant women.


Lactating women


For the first 6-12 months after giving birth, women who breastfeed their baby should not participate in an intermittent fasting plan. Lactating women require more food intake than normal to keep breast milk supply up. As well as this, if you are breastfeeding, you burn a lot more calories than you normally would - a biological feat that helps people to lose weight after giving birth. For this reason, lactating mothers are advised to eat larger meals and more frequently, often during the night, to keep energy levels up and be able to survive early motherhood. 


As a mother who breastfed my baby, I couldn’t agree more with this. Imposing a strict eating schedule such as intermittent fasting at a time when you are exhausted and dealing with a tiny human who needs you constantly can be a recipe for disaster. Both nutritionally and common sensically, intermittent fasting during lactation is not a good idea. 


Adults under 18 and over 65


The nutritional needs for people in these age groups are a little different than the average adult. A younger person is still growing and developing, and therefore needs to consume regular meals without any restriction. 


On the other end of the age scale, an older person might be taking medication needing meals for optimal absorption or already have a reduced appetite and need more nourishment. 


In both cases, medical intervention would be needed to implement any kind of intermittent fasting. In other words, discuss with your doctor. 


Anyone with nutritional deficiencies and/or a history of eating disorders


A healthy relationship with food is so phenomenally important in any healthy eating journey. Unfortunately, in people who suffer from nutritional deficiencies or eating disorders, this relationship may be impaired. For this reason, any form of restriction in eating is not advised, including intermittent fasting.


This is also the case for those with a body mass index less than 18.5 (the lower limit for a healthy weight).


People taking medication


Talk to your health care professional before starting with intermittent fasting, as medication is often affected by food intake. For example, warfarin, a common blood thinner, is impacted by dietary intake of vitamin K (found in green leafy vegetables). Some medications need to be taken with food for optimal absorption, such as pain killers like celecoxib (a non-steroidal anti-inflammatory drug). There are also medications that depend on food for dosage adjustments, like insulin. 


Cheat codes for Intermittent fasting at any age



Okay! Now that we’ve gotten all the information out of the way, let’s get down and dirty with the fun stuff! Below you’ll find some cheat codes that will fast track and turbo-charge any intermittent fasting plan


Cheat code #1 - extend your fasting period slowly


Start small! Cut out night time snacks and eat dinner 30 minutes earlier than normal. Then do the same on the other end! Eat breakfast 30 minutes later than you would normally (so long as it fits into your schedule) and voila! You have already extended your fasting period by 1 hour. 


Cheat code #2: Change your eating pattern during your eating phase


Use intermittent fasting as a way to experiment with what eating pattern works best for you. Adding more nutritious food into your eating plan is one way to do this. Eating energy heavy foods such as carbohydrates earlier in the day and stable energy foods such as lean protein and healthy fats closer to the fasting period could be another. Either way, use this experience to create new healthy habits that will follow you down the track.


Cheat code #3: Break the hand to mouth habit during the fasting phase


Water and plain tea are great for the fasting period, especially if you have a hand to mouth habit or are a constant craver. 


Let me explain this one a little further, because it can be a seriously hard thing to break, but also change your entire eating pattern if you manage to do it effectively. A hand to mouth habit is where the craving you have is actually the physical act of putting food from your hand into your mouth. 


A similar thing has been studied in smoking, and changing the habit pattern (cue, action and reward) by changing the action can be super effective in breaking the habit. In smoking cessation, one of the things I usually suggest is to replace the hand to mouth habit, particularly in the morning, with another activity - drinking water, eating a fruit or going for a walk. 


Translating this into a technique to use in intermittent fasting, if you snack during the nights, once you begin intermittent fasting, substitute a tea, or water as something you can bring to your mouth to satisfy the action phase of your habit. Sometimes, this simple act of hand to mouth can stop snack cravings! It’s not always about the food - listen to what your body is telling you.


Final Thoughts


At the end of the day, the best intermittent fasting schedule is one that you can stick to. No matter what you choose, make sure it is sustainable for your life at the current stage you’re at!


Let me know in the comments below if you’ve ever had to consider your age before choosing intermittent fasting! If you want more information, as always, feel free to book a chat with me and we can always discuss something that will suit your specific needs. 



References (For studies, please click on links in post)


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