Metabolism When Fasting : Effects of Intermittent Fasting on Metabolism

Last Updated on July 20, 2022 @

Read Time : 8 minutes

In this article, we’ll discuss all you need to know about Metabolism When Fasting.

Here you’ll learn:

  • Fasting as a Method of Weight Loss
  • Effects of Short and Long Periods of Fasting on Metabolism
  • How Intermittent Fasting Can Boost Your Metabolism
  • How to Keep Metabolism High While Fasting
  • The Role of Exercise in Boosting Metabolism when fasting and much more!

So if you’re looking to boost your metabolism and burn extra fat while fasting, you’re going to love this article.

Let’s get started.

Intermittent Fasting for Women: The Complete Guide (2021)
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Fasting as a Method of Weight Loss

Intermittent Fasting is a simple method to lose weight.

The fundamental idea behind fasting to lose weight is to cut down on the amount of food you eat in a day and let the body use its stored fat, for metabolic processes.

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But let’s stop for a second and really understand what metabolism is.

Metabolism is the process in which your body burns resources to produce energy. So the process of metabolism is the reason you get energy to do your tasks throughout the day.

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How does Fasting come into play here?

When you eat food, your body will readily take that to produce energy. In intermittent fasting, you temporarily restrict any supply of food to the body to use. This forces it to shift to the stored fat for energy. You can see how strongly connected metabolism and fasting really are. 

And the reason fasting is such an effective method is because you’re putting absolutely no extra effort. All you’re doing is restricting your food intake for a certain time; to burn stored fat.

How Intermittent Fasting Can Boost Your Metabolism

Intermittent Fasting is a calorie restriction method where you restrict your meals to a particular time period in the day and fast for the remaining hours. What matters here is not what you eat but when you eat.

In IF, you're not fasting for long hours at a stretch. Rather, the focus lies on fasting for short hours, only till an extent where your body is at an advantage.

A study shows that metabolism when fasting can be boosted through shorter fasting periods while maintaining optimal insulin sensitivity levels and hormone levels. 

Moreover, Intermittent Fasting has proven to be more effective in burning fat than traditional calorie restriction methods. 

IF has an end purpose of building healthier eating habits. Here, you first eliminate unintentional eating by eating only during specific hours. After that, you start formulating an overall healthier diet that is more natural and fits your daily routine.

As mentioned a few times already, approach fasting with an attitude of building a healthier lifestyle and not just as a weight loss mechanism.

When does Fasting actually Reduce Metabolism?

Let’s address a few questions that are frequently asked about fasting - 

  1. Does metabolism slow down while fasting? 
  2. Does extended fasting slow metabolism?

When fasting for long periods, your body goes from burning glucose and glycogen (stored form of glucose in the body) to burning body fat which is another form of stored energy. 

Since most people these days have plenty of stores of body fat; fasting by itself is rarely the problem when it comes to slowing down your metabolism.

However, if you fast for too long and drastically reduce your calorie intake, it’ll lead to the slowing down of your metabolism when fasting by as much as 30%. This phenomenon is called Adaptive Thermogenesis

Moreover, your muscle tissues are the primary areas of energy consumption. So to reduce that consumption and to sustain, your body will even start burning muscle mass for energy.

Your metabolic rate would drop even further as the muscle tissues are reducing and thus in the long run. Instead of losing weight, you’d be gaining it. Also, as your metabolism drops, you’ll feel tired very often and suffer headaches, among several other health problems.

Is this what you could expect from Intermittent Fasting as well? Or in simpler words, is intermittent fasting bad for metabolism?

In almost all cases, intermittent fasting has positive benefits and does not create any such health problems. Given that you follow a proper routine and eat well when you are not fasting, you can live a healthy life while maintaining an IF lifestyle. 

Instead of worrying about the long-term effects of fasting on metabolism, focus on maintaining a balance between fasting and healthy eating. Maintain a healthy relationship with food.

Intermittent Fasting vs Irregular Fasting
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How to Keep Metabolism High While Fasting

While shorter fasting periods help in maintaining metabolic levels, it won’t improve your metabolism. You can make other changes in your lifestyle to boost your metabolism and burn more fat. Let’s look at a few ways you can do that.

1. Eat More Protein

When you eat food, your body gets a slight boost of metabolism to burn up what you’ve eaten. 

This is called Thermic Effect of Food (TEF). It’s simply to process the nutrients in the food that you’ve eaten. 

Now, eating protein results in a high rise in TEF. In comparison to carbs that give a 5-10% increase in metabolism or fats that give a 0-3% increase, protein gives a whopping 15-30% increase in your metabolic levels!

Not only does protein help in body mass recovery, essential to avoid muscle loss while fasting, but it even boosts your metabolism. 

Moreover, protein takes more time to digest than fats and carbs, which makes you feel full for a longer span of time. 

 For example, replacing carb heavy meals like Pasta or Bread with a generous serving of meat like a Steak; can keep you full longer and help you eat fewer overall calories in the process.

It must be clear now that having a good protein diet is essential for your body in a lot of ways.

Sources of Protein
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2. Drink Lots of Water

And we really mean lots of water!

There’s a number of reasons why drinking at least 12 cups of water each day should be a priority. 

One, is the temporary metabolism boost that water gives to your body. Research suggests that drinking 2 liters of water in a day results in an energy expenditure of about 400 KJ and increases your resting metabolism by 10-30% for an hour.

Another study shows that overweight adults who drank half a litre of water before their meals lost 44% more weight than those who directly had their meals.

Moreover, drinking lots of water will trick your body into thinking that it’s full. This is a great way to fend off any hunger pangs that are troubling you during the day. 

According to Healthline, drinking cold water can also help in increasing your metabolism when fasting. This is because your body will try to generate heat in your body and thus burn calories for it.

Replacing your sugary drinks with water will help you lose weight faster by cutting down empty calories. To know more alternatives to these drinks click here
Benefits of Hydration
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3. Avoid Sitting for Long Hours

It’s clear why this is an important element of this list. Sitting in a spot for long hours will result in fewer calories being burnt. This is because one of the greatest contributors to daily caloric expenditure is something called N.E.A.T (Non Exercise Associated Thermogenesis)

N.E.A.T is made up of activities that we do through the day that aren’t direct exercise. From movements such as doing household chores to something as miniscule as fidgeting - they all add up to caloric expenditure via N.E.A.T

Obviously, if you spend most of your day sitting; you significantly reduce calorie expenditure coming from N.E.A.T. So try to avoid long hours of sitting and occasionally move around and about. 

If your work demands long periods of sitting, set an hourly timer to get up and walk around a little. This will even help you stretch your body and feel a little refreshed.

Girl working on laptop
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4. Drink Green Tea Or Coffee

Tea and Coffee are great antioxidants. Having Green tea throughout the day will help flush out toxins from your body and even lose weight. 

Plus, studies even suggest that Green Tea can boost your metabolism by 3-5%.

Coffee, preferably black, is another drink that helps boost your metabolism

They provide another way of keeping yourself hydrated other than simply drinking water. 

To know more about the different kinds of drinks you can have while fasting, check out this article.
Girl Drinking Green Tea
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5. Eat More Spices

Eating spices is yet another method to improve your metabolism and increase energy expenditure. Spices help burn fat in your body while even temporarily increasing your metabolism to digest that spicy food. It will also consistently maintain your metabolism when fasting at optimal levels

Not only that, spices also make you feel full with lesser food intake. Club up satiety and high energy expenditure and the benefits become extremely clear. 

To give you a brief on the best spices to add to your diet, here’s a list for you to follow:

  • Cayenne Pepper - Cayenne Pepper has a compound called Capsaicin that’s also found in bell peppers. This compound is what is responsible for the spice and causes an increase in thermogenesis, leading to higher energy expenditure.
  • Turmeric - Turmeric is often an addition to curries and carries a ton of health benefits. A study showed massive improvements for those suffering from metabolic syndrome and obesity. Moreover, it even showed anti-carcinogenic properties. 
  • Mustard Seeds - Just like Cayenne Pepper, mustard seeds boost metabolism and even have antioxidant properties. This makes them a great addition to your meals.
  • Ginger - Ginger has anti-oxidant and anti-inflammatory properties that help to fasten recovery and weight loss. A study conducted showed that along with weight loss, ginger can also help with cholesterol levels.
  • Cumin Seeds - Cumin Seeds help in burning fat and hold a ton of fiber. Studies show that cumin powder can help in reducing triglycerides, further reduce the risk of cholesterol and contribute to weight loss.
  • Black Pepper - Black Pepper has a compound called piperine that increases thermogenic activity that helps to lose weight.
  • Cinnamon - Cinnamon is advised for those who are diabetic or are struggling with low insulin sensitivity as it improves glucose metabolism by three times. Better glucose metabolism levels will further aid weight loss.
Spices that Boost Metabolism
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6. Reduce Processed Food

Try to avoid packaged food as much as possible - especially processed carbs. Eat home cooked meals as much as you can, to know what you’re putting inside your body. 

Plus, when you’re doing Intermittent Fasting, restricting your meals to a specific period means lesser meals to worry about. So, you can prep those meals in advance as it will be much more manageable while following an Intermittent Fasting plan. 

Try shifting to coconut oil for cooking as it’s a much healthier cooking oil than others.

7. Get Quality Sleep

Ideally, as an adult, you should sleep for an average of 6-8 hours everyday. Especially, while fasting, your body needs more time to recover and produce energy for the next day. 

A study shows that sleeping too little can alter glucose levels and increase the risk of metabolic syndrome.

Moreover, according to WebMD, sleeping too little can prompt you to eat bigger portions of food and increase cravings for carb-rich meals. 

So make sure you sleep well and give your body the rest it needs.

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While a good diet is crucial to continue to maintain a good metabolism when fasting, exercising is yet another important element that you must include in your lifestyle. So, let’s look at a few types of exercises you can do to improve your metabolism even more.

7 Ways to Keep Metabolism High While Fasting Infographic
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The Role of Exercise in Boosting Metabolism

As previously mentioned, exercising helps boost your metabolism. The greater the intensity of the exercise, the greater its effect on metabolism.

We’ve listed down a few metabolism boosting exercises for you.


High Intensity Interval Training (HIIT) is one of the best exercising methods out there to boost metabolism when fasting and lose weight. It involves short and quick bursts of activity that  helps burning fat fast. You can find several workout routines online.

Quick HIIT Home Workout for Women
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2. Steady State Cardio

Steady State Cardio like running is great for people who are just starting out with cardio exercises. It helps to build stamina and increases your metabolism levels. 

However, your metabolism when fasting may flat line if you continue the same routine for too long. In order to keep your metabolic levels high, you must change up your routines every now and then. Switch up your intensity and duration levels to keep it challenging. But give yourself rest days in between to ensure your body gets time to recover.
Girl running on treadmill
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3. Weight Training

Research has shown that resistance training helps prevent any muscle loss that may occur while fasting and even increase metabolic rate.

Moreover, resistance training improves hyperandrogenism (an excess release of male hormones). This further improves reproductive health in women and reduces fasting glucose levels.

You can either use external weights or try calisthenics (using your own body weight to exercise). Combining weight training with aerobic activities will further boost your metabolic levels. Thus, divide your workout time to include a bit of cardio as well. 

If you lack access to a gym, you can use resistance bands to work individual muscles. They’re easy to use, cost-effective and provide great results. It’s a great option for you to start out with resistance training, providing a wide range of resistance levels to choose from.

Girls lifting weights
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Something to consider

As promising as heavy exercising during fasting can be, it may lead to you feeling tired or even cause fatigue.

This can occur especially when your fasting period is dragged on too long or when you’re eating insufficient food during your feasting period.

Monitor your body’s energy levels and find a balance in terms of the intensity of exercises so that you benefit from it without tiring yourself out completely. 

Consult a doctor if you feel uncomfortable at any point while fasting. Based on your lifestyle, your fasting schedules may need some alteration if you feel tired or encounter any problems.

Wrapping it Up

If you’re making an effort to fast, why not make the best of it? Create an IF routine that maximizes your growth. A fasting plan that helps you regulate your diet and improves your metabolism when fasting should be your goal. 

Eat nutritious food with the right balance of protein, carbs and fats. Maintain a consistent and progressive exercise routine. Monitor your lifestyle with an intention of being healthy, both mentally and physically. These are three parameters you must live by. The more religiously you follow the pointers mentioned in this article, the greater benefits you will end up reaping.

Now it’s Your Turn

There you have it: Our Comprehensive Article on Metabolism When Fasting.

Are you excited to try out Intermittent Fasting?
Which form of exercise are you keen on trying to boost your metabolism when fasting? -  HIIT or Weight training?  Would you go for Green Tea or Coffee to burn that extra fat?

Let us know by leaving a quick comment down below.

Now it's your turn - Comment Below
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Metabolism when Fasting - Effects of Intermittent Fasting on Metabolism
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