Intermittent fasting seems like a dream for people who want to lose weight: you don’t have to change what you eat, only change when you eat it.

Yet, like every other diet or eating plan, it’s not always so straightforward, and weight loss is never linear. That’s why it’s so easy to start strong and fade away as the frustration mounts up with yo-yo’ing and weight fluctuations.

Studies show that when following a low-calorie diet, plateaus tend to happen around the 6-month mark. While intermittent fasting doesn’t mean you’re low calorie, it’s a common side effect when eating fewer hours.

Here are science-backed solutions to try if you’re not losing weight on intermittent fasting or have hit an intermittent fasting plateau.

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Why am I not Losing Weight on Intermittent fasting?

While fasting has many health benefits, most people do it for weight loss.

Below, we’ll answer the central question of why you may not be losing weight while intermittent fasting (otherwise known as an intermittent fasting), with eight suggestions to troubleshoot.

But before we get into it, we want to set the stage by quickly answering a few common and relevant questions, as well as sharing with you the science of how intermittent fasting works in the first place.

So, let’s get started with these common questions from our readers and clients:

How long does it take to notice weight loss from intermittent fasting? If you’re measuring weight loss accurately, it will take one to two months to see any changes. If, you’ve been fasting for two weeks and experienced no weight loss, be patient and hang in there. However, if you’ve lost weight in the past with IF but now have stalled for a few weeks, you’re likely experiencing the dreaded weight loss plateau.

Is it possible not to have any results during intermittent fasting? Anything is possible, but it’s highly unlikely. At the minimum, you should feel more energized, have less bloating, and it should feel easier to control your hunger. If you haven’t felt any benefits, either your diet and lifestyle are already perfect, or you’re perhaps not eating enough or fasting long enough. Read on as we talk about this below.

Why am I not losing weight on low-carb or keto and intermittent fasting? Just to put it out there, we are against low-carb and keto diets. The science is there, but in reality it shakes out to people cutting out too many carbs. Your body needs all of the macros, carbs included, to become healthy. We promise that you can still lose weight, feel your best, and build strength while enjoying carbs.

Why am I gaining weight with intermittent fasting? There’s a good chance your metabolism is down. This happens when people eat too few calories which is very easy to do while fasting. Again, more on this below.

Now that we have those out of the way, it’s important to understand why intermittent fasting is recommended for weight loss in the first place.

How Does Intermittent Fasting Help You Lose Weight?

Without getting too deep into the science, intermittent fasting helps you lose weight in two ways:

1) Helps your body burn stored fat.

Once reaching a fasted state, your body will start burning the fat stored in fat cells for energy. This is because you’ve already used up the readily available glucose (aka the simple sugars from carbohydrates) from your last meal.

How long does it take to reach a fasted state? Studies point to between 12 and 36 hours. Wow, that’s a big range, but it’s all dependent on your diet, insulin sensitivity, and exercise levels.

2) Decreases insulin sensitivity and increases metabolic flexibility.

As your body adapts to fasting, both insulin resistance and metabolic flexibility improve, making it easier to manage and lose weight in the future.

Metabolic flexibility is how easily your body can switch from burning carbohydrates to burning fat. (Your body also burns protein 5% of the time, so we’ll ignore that for now as it’s not a predominant fuel source.)

A healthy body burns both carbohydrates and fat. In fact, your brain needs a constant supply of glucose to operate, so without carbohydrates in your diet, your body will start breaking down skeletal muscle to get it.

In other words: never cut out carbs from your diet! For those of you following a strict keto intermittent fasting plan, please eat carbs again and your plateau will be solved.

How do you know if your body is burning carbohydrates or fat? Anecdotally, you’ll feel more energized and focused while burning fat. But generally, until you’re in a fully-fasted state, your body will be burning a mix of carbohydrates and fat at the same time.

If you’d like to have a more precise measurement, at-home devices like Lumen measure your metabolism in real-time and can tell you if your body is burning fat or carbs.

OK, let’s get back to it.

Intermittent and extended fasting bundle - printable pdf guide

The Proven Fasting Bundle (Printable PDF Guide)

Read by 143,364 fasters in 2022 alone, the Fasting Bundle is the structure and tools you need to succeed.

  • Intermittent and alternate-day fasting meal plans
  • Checklist for before, during, and after a prolonged fast
  • Benefits, challenges, and a beginners how-to guide

Plus, we're just an email away for support.

Not Losing Weight on Intermittent Fasting

Now that we’ve gone through how intermittent fasting can help you lose weight, let’s troubleshoot what might be leading to weight gain, a lack of weight loss, or an intermittent fasting plateau.

You may notice that there is some similarity to what you may have read before about a general weight loss plateau. That’s because weight doesn’t change due to one thing — and what works for you may not work for others.

When thinking about what contributes to weight loss plateaus, consider activity levels, stress, eating habits, exercise routines, sleep, and even medication. Your best bet is to keep good notes and try a variety of things until something works.

Here are things to consider when you’re not losing weight on intermittent fasting.

1. Measure How Your Body Responds to Fasting in Real Time

Okay, we’ll cut right to the chase because you can take the guesswork out of everything and buy a device that will tell you when you’re burning fat and when you’re burning carbs in real time. It’s that simple, and it’s the same one we mentioned up above.

A few years ago, this tip wouldn’t have existed. For years, the only way to get metabolic data was in a lab. This was far too expensive and inconvenient for anyone who wasn’t a professional athlete.

But now, you can get this information immediately and at home with a little device called Lumen.

It works like a breathalyzer and measures the carbon dioxide in your breath. Not only will it tell you that you’re burning 25% fat and 75% carbs at that exact moment, it will make recommendations on what to eat today to optimize your metabolic flexibility.

We’ve used it for months now, and it’s mind-blowing. We discovered that our bodies use fuel completely differently, despite eating all of the same meals. I discovered that my fasting window is much shorter than Ryan’s — something the device helps you figure out.

So if you’re ready to zero in on your weight loss, the Lumen is the most helpful thing you can get while intermittent fasting if you have $250 to spare and our $50 off code RYANANDALEX.

Focusing on metabolic flexibility is the best way to lose weight consistently because it is influenced by four pillars—movement, food, sleep, and stress. As you optimize these, weight loss comes more easily.

2. Your Fasting Window is Too Short

People generally enter their fasting state between 12-36 hours.

If you’re not ready for a multi-day fast (let alone a 3-Day Fast which was incredibly eye-opening for us), you may be underestimating how long it will take for you to “flip your metabolic switch” into the fat-burning zone. To better understand the timeline, see our article titled, ‘Stages of Fasting by Hour.’

We get this question all the time: “Why am I not losing weight on a 16/8 fasting plan?”

While the most common intermittent fasting schedule is the 16/8 (16 hours of fasting with an 8-hour eating window), 16 hours is not a magic number. It may be too short. Try fasting for longer to see if you feel more energized and see better weight loss results.

Note – It is also possible to fast for too long. We discovered this while using our Lumen device. When you over-fast, the stress causes your body to leave the fat-burning zone and move back into the carb-burning zone. This is pretty difficult to pinpoint without measurements, which is another reason to consider using a metabolism tracker.

Lastly, make sure you’re not unintentionally breaking your fast early by putting creamer in your coffee or eating a banana before your fasted morning workout.

3. Your Diet is Too Heavy on Simple Carbohydrates

While the draw to intermittent fasting is that you don’t have to change what you eat, you can maximize your benefits by eating a well-balanced diet. Simple carbs are often the root cause of an intermittent fasting plateau.

Mainly, if you’re eating too many simple carbohydrates (white bread, pastries, junk food, etc.) your blood sugar, or glucose, levels will be elevated for longer. That means you must fast longer so that your body can finish burning carbohydrates before moving on to burning fats.

Again, this doesn’t mean cutting out all carbs — we don’t condone diets like keto for this reason. Simply be aware that it will take longer to get to a fasted state.

What should you be eating? We recommend fiber-rich foods, homecooked meals, lots of plants, tons of water, and only foods that your great-great-grandmother would recognize. Avoid ultra-processed and high-sugar foods and drinks. We also highly recommend LyfeFuel as an excellent source of protein and macronutrients

4. You’re Eating Too Few Calories

Yes, you read that right. In our experience working with thousands of clients, the vast majority struggle to lose weight because they are eating too few calories rather than an excess. 

Intermittent fasting can make this problem even worse. It’s easy to eat less than you normally would simply because there aren’t enough eating hours in the day. 

This is surprisingly common as it’s in our heads that fewer calories equal weight loss. However, the downside is that our bodies might enter a food scarcity mode, hold onto fat reserves, and slow down our metabolism.

To avoid this, we walk you through how to calculate and track your daily calories in our article, the ‘30-Day Weight Loss Challenge.’

So, how many calories should you eat on a 16/8 fast? The same as you would during a normal eating window. 

As a rule of thumb, never consume less calories than your BMR. Adult women should never eat less than 1,200 calories a day, and men 1,600. This is no matter how petite you are or how much excess weight you have to lose.

5. Use More Numbers than Just the Scale

It’s easy to get fixated by the number on the scale, but that’s only one weight loss measure of many. In fact, it might be one of the least helpful.

When losing weight with intermittent fasting, we prefer using a combination of body measurements (like your waist, thighs, etc.) and “before” and “after” photos to track progress. We share the exact body measurement chart (free PDF download) in our article titled, ‘The 5 Most Effective Ways to Measure Weight Loss.’

Research shows that with enough protein and exercise, you can maintain and gain muscle mass while intermittent fasting. Therefore, if the number on the scale isn’t budging, you may still be losing fat but simultaneously gaining muscle weight.

So, if you’re not losing weight on intermittent fasting but losing inches, stay the course. That scale victory loss of belly fat is inevitable. 

If photos and body measurements aren’t your thing, we recommend this low-cost scale we use at home. It pairs with a free app and shares metrics like body composition, muscle mass, and body fat percentage.

6. Change Up Your Exercise Routine

While you may be intermittent fasting in order not to diet or exercise, hear us out on this one. A good exercise plan is easily the best way to speed up weight loss on intermittent fasting. 

Intermittent fasting weight loss is dependent upon depleting blood sugar levels after fasting, so as to kick your body into fat-burning mode. One way to help get yourself over a weight loss plateau while intermittent fasting is through exercise.

For the 24 hours after exercising, your glucose levels will continue to drop.
In fact, additional research has shown that you can fast for fewer hours with the same results as long as you exercise.

We recommend resistance training and strength training to build muscle to lose weight and have several free plans that you can start today. For our best exercise tools, head over to our Work Out At Home Page.

7. Eat Most of Your Calories Earlier in the Day

In a study published in the journal Obesity, a group of overweight and obese women ate most of their calories either at breakfast or dinner for 12 weeks.

At the end of the study, the breakfast group lost 2.5 times the weight as the dinner group! That’s pretty incredible, and incredibly simple.

If you’ve reached an intermittent fasting plateau, try shifting most of your calories to the morning. Generally, it takes about 2 weeks for your body to become adjusted to your new schedule, so don’t worry if you find yourself craving more food at night. Your body will adjust with time.

Closing Thoughts on Intermittent Fasting Plateau

Being stuck on a weight loss plateau is no fun but a natural part of the weight loss process. If you’ve hit it, don’t get too discouraged as you work your way through it. We typically see people stuck on their plateau for 4-8 weeks.

Without exact data from a Lumen device or another metabolism tracker, it’s difficult to pinpoint your ideal fasting window, which is critical to maintaining weight loss while intermittent fasting.

We’ve shared the most likely tips to kickstart your weight loss and beat the intermittent fasting plateau. Keep a good journal and know that what may have worked for you in the past won’t necessarily work for you again in the future.

There are many factors that contribute to weight plateaus, but keep it up and you’ll break through. For more great resources, such as our guide on how to lose 20 pounds with 15 strategies that cost nothing, head over to our Weight Loss Page.

Feel free to download our Fasting Bundle to help you plan, track, and succeed with both intermittent and prolonged fasting.

Leave any specific questions about your intermittent fasting weight loss plateau in the comments below. We prefer that to email because the discussion helps all future readers. Thanks!

For more resources and guides about fasting, such as our guide to intermittent fasting and sleep, head over to our Fasting Page.

Intermittent and extended fasting bundle - printable pdf guide

The Proven Fasting Bundle (Printable PDF Guide)

Read by 143,364 fasters in 2022 alone, the Fasting Bundle is the structure and tools you need to succeed.

  • Intermittent and alternate-day fasting meal plans
  • Checklist for before, during, and after a prolonged fast
  • Benefits, challenges, and a beginners how-to guide

Plus, we're just an email away for support.

As Seen In Feature Bar Ryan and Alex Duo Life

Hey we're Ryan and Alex

The creators of Ryan and Alex Duo Life. We are a husband-wife duo and “lifestyle engineers.”

After eight years working in the corporate world as engineers, we left our high-powered jobs to tackle our true passion — helping couples engineer their best lives.

The synergy of our engineering minds and ten years of health coaching experience produced Ryan and Alex Duo Life. Our mission is to help you transform your bodies, minds, and relationship as a couple.

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