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Intermittent Fasting is another HUGE hot topic right now! I am guessing you’ve heard something about it, tried it yourself or know someone who has. Eat Move Thrive dietetic intern, Katelan has dug deep into the science to bring you the scoop! This is a topic that health practitioners debate-dietitians included. Take a few minutes to read this post and please reach out to me with any thoughts or questions! I would love to hear from you.



Intermittent Fasting

By Katelan Head, Dietetic Intern


Whether you work in the nutrition field or just love to learn about food and health, you may have noticed that new dietary practices come and go faster than a ready-to-eat avocado. From eating foods based on your blood type to cutting out major food groups, it’s hard to keep track of what’s a proven method of eating versus a quick fix and possibly harmful fad. One of the major differences between intermittent fasting and a typical diet trend is that the focus is on meal timing versus what you actually eat.


What is Intermittent Fasting?


Intermittent Fasting (IF) is a style of eating that alternates between eating and periods of abstaining from food or fasting for a set amount of time. This can mean limiting the food you consume during certain days of the week or during specified hours each day. IF is meant to help the body burn fat while in a fasted state. Depending on who you talk to or ask, IF can mean a multitude of different things to different people and can be followed in multiple ways.

When we are eating, our bodies use glucose from food for energy. Glucose is stored in the liver and muscles and it can be released into the bloodstream when the body needs it.  Glucose is brought into our cells by the hormone insulin and if we don’t use all of it, it can be stored in fat cells. During a time of fasting, our insulin levels will decrease and release the stored glucose to be used as energy. Allowing insulin levels to continue to decrease for a long enough period of time can allow the body to burn fat which can potentially lead to weight loss and other health benefits.


Are there different methods of IF?


There are several different patterns of IF that can be used and that can be tailored to an individual’s lifestyle and goals. A popular form of IF is the 5:2 method which involves eating normally for 5 days of the week and consuming 500 calories on the other 2 days of the week. Individuals can choose which day they decide to fast and are recommended to consume one 200 calorie meal and one 300 calorie meal throughout the day.

Another popular form is the 16:8 or 14:10 method where you have set eating and fasting windows. So you can choose to fast for 16 hours and eat for 8 hours (eating from 10am-6pm each day) or fasting for 14 hours and eating for 10 hours. Other methods include the 24-hour method involves fasting for 24 hours either once or twice per week and alternate day fasting where you fast or limit calories every other day.


Any noteworthy benefits?


According to some studies, IF has shown to be effective for weight loss, lowering blood pressure and improving overall metabolic health. Other studies have also shown an increase in mood and enhanced cognition. When looking at IF on managing Type II diabetes, one study showed that it helped reduce blood sugar levels and reduced insulin levels. Another study found that IF can help lower inflammatory markers and oxidative damage which helps reduce disease.

Other noteworthy benefits based on studies conducted on rats included increasing the growth of new neurons and protecting the brain against damage as well as increasing longevity and extending your lifespan.


Any negative risks I should know about?


Since IF has not been studied over long periods of time, it’s difficult to determine any long-term negative health risks. However, anyone interested in trying IF needs to be aware of some of the negative consequences that can be associated with abstaining from food for long periods of time.

Time restricted eating can be a useful tool for certain individuals to help the body rest in between periods of eating but in others it can promote unhealthy eating behaviors. Due to the restriction around when you are able to eat food, this eating style could exacerbate binge eating, emotional eating and even develop into an eating disorder. While IF can feel like a more flexible approach for some, for others it can create a sense of stress and anxiety around eating.

For individuals who engage in physical activity, IF can also have a negative effect on energy levels and muscle break down. If you tend to exercise first thing in the morning, working out in a fasted state may backfire since you don’t have readily available energy from food. Individuals may become light headed, lethargic and anxious depending on the intensity of their workout.


Overall thoughts on IF?


This post is an opinion piece and is simply meant to inform individuals about some of the current research on intermittent fasting. It should be noted that the research on IF is very nascent and long-term outcomes need further investigating.

While some research shows individuals who followed IF lost weight, none experienced long term weight loss which makes the data inconclusive. Researchers are also unsure whether it’s the time restricted eating associated with IF that causes weight loss or just that individuals are not eating as much due to eating during a shorter window of time.

IF may be a helpful tool for individuals who are overweight or obese to stop overeating and help the body shed fat. It may also be helpful for individuals who are noticing low energy or an inability to focus throughout the day. However, IF is meant not for everyone. Anyone with a history of disordered eating patterns or mental health disorders should avoid IF and consult a dietitian or mental health counselor for support around eating styles.

If Intermittent fasting is something that interests you, it may be worth considering experimenting with avoiding nighttime snacking 2-3 hours before bed and trying an overnight fast of 12 hours. Be mindful how your body reacts and adjust accordingly. The ultimate goal should always be to incorporate a style of eating that creates energy, sustainability and helps you thrive. Always reach out to a Registered Dietitian Nutritionist before starting IF for support and guidance. Monika is happy to answer your questions on IF and provide support wherever you’re at with your health journey.