Mistakes with Intermittent Fasting that Ruins Your Results

author avatar Dr. Eric Berg 08/31/2023

A sign saying Mistakes with an eraser symbolizing erasing your mistakes

You’re doing intermittent fasting but are about to give up because you aren’t getting the results you expect, including weight loss, increased energy, and better mental clarity. You're carefully adhering to your fasting window and eating window.

Yet you're feeling awful, and about to give up.

Please don't! You may be making one of these 8 common mistakes with intermittent fasting.

Let’s take a look at what they are, so you can correct them and have success with fasting.

#1 Going Too Fast Into Fasting

If you move too quickly into fasting, you don’t give your body a chance to adapt to longer periods between meals especially if you’ve been eating the standard American diet of highly processed and high-carbohydrate foods that are laden with sugar and chemicals.

The reason why moving too quickly after years of a standard American diet is because you’ve almost certainly created a blood sugar problem for yourself, then you try to fast when your blood sugar is dysfunctional. For example, you jump from not fasting at all to one meal a day (known as OMAD). This is like trying to go from zero to 90 miles per hour while the engine’s carburetor is clogged with gunk.

What will happen is, you’ll be extremely hungry, very irritable, probably cheat by eating when you believe you shouldn’t, then feel discouraged and give up.

When, in fact, if you’d eased into fasting more slowly, you’d be working with your body instead of against it, making fasting success more likely.

I admire your willingness to jump right in, but sometimes you just have to slow down a little to reap the rewards.

#2 You Don’t Realize You’re Eating Too Many Carbs

Uncooked rice in a wooden bowl

Carbs can sneak into your diet, even when you think you’ve cut them low enough. Sometimes this is called “sort of keto”. When I talk with some people, they tell me they’re doing the ketogenic diet and it’s not working.

But when I ask them what they’re eating, we uncover the issue.

Usually, they’re eating a high amount of carbohydrates in items like fruit, rice, and sweet potatoes. And they don’t realize these foods contain carbs; enough of them to wipe out your ability to get into or stay in ketosis (link and explain).

A comparatively small amount of carbs can knock you out of ketosis for up to 2 or 3 days. It takes awhile to get into the state of ketosis, so the last thing you want to do is knock yourself out.

If you’re consuming high carbs without fully realizing it, this could be the reason you’re not seeing results from intermittent fasting.

#3 You’re On The 5-2 Plan

On this plan, you eat whatever you want for 5 days. Then, for 2 days, usually weekends, you bring your calories down to 500 per day.

You can see the problem here.

First, all week long you’re eating whatever you want. Which, let's face it, usually includes unhealthy junk or processed food. Then tiny meals for 2 days? This doesn’t give you enough time to fully adapt to the state of ketosis. You’re going to struggle. It will feel unpleasant.

You’re then likely to give up and say fasting isn’t right for you.

If you’re going to seriously try fasting, then fast properly. 500 calorie meals won’t let your body get into ketosis, with all its benefits.

#4 Too Few Calories And Too Few Nutrients

With this situation, you’re fasting, but when you do eat you’re eating too few calories thus getting too few nutrients to support your health.

Here’s the thing. When you’re lowering the number of calories you’re consuming, you’ve got to increase the nutrient density of the foods you’re eating or at the very least enhance it with supplements.

With me so far?

The purpose of food is twofold: one is as fuel, the other is its nutrients.

When you fast, you’re tapping into the fat stored in your body. Which is excellent; this is how you burn body fat and lose weight.

But in addition to this, your body needs nutrients to thrive over time.

If you eat fewer and non-nutritive calories, at first you won’t notice any impact. But a few weeks or months later, you’ll notice effects like hair loss, loose teeth, and bleeding gums.

Although I’ve talked about too few calories, I don’t want you to calorie count. It’s just that your calorie intake will naturally decrease as you eat fewer meals. Instead, focus on getting the highest quality food in order to get the variety and quantity of nutrients you need.

Which leads me directly to the next point.

#5 Consuming Low-Quality Ingredients

You’re fasting; say, eating just once or twice a day. That’s excellent!

Except when you do eat, the food isn’t very high quality.

A picture of common junk foods like burgers and pizza

For example, let’s say that instead of whole, natural food, you’re consuming something made with powdered soy protein isolate. (Which is in many different products where you might not expect it.)

This is a classic example of a low-quality ingredient that’s easy to consume without realizing it. Over time, you’ll begin to look unhealthy. I’m not saying you’re going to look like something the cat dragged in, but you’re certainly not going to look radiant and healthy.

#6 Not Enough Potassium And B Vitamins

Your body needs a significant amount of potassium every day, along with B vitamins and trace minerals.

Think about this: you’re fasting to improve your health. Fasting triggers all kinds of beneficial genes such as ones that promote anti-aging, lower inflammation, and grow new brain tissue. In order for you to get the full benefits of these genes being switched on, your body needs certain nutrients to support the gene action.

Along with looking dragged out and unhealthy, you could end up with heart palpitations, hair loss, and other signs of dysfunctional health.

#7 You’re A Vegan On The Keto Diet But Not Consuming These Nutrients

It’s certainly possible to successfully fast as someone who follows a vegan way of eating, especially if you’re on the keto diet.

But where you can run into problems is if you’re not taking vitamin B12, something called DHA, and the mineral zinc, along with iron.

I’ll explain.

Without these nutrients, you can run into problems similar to what I’ve already described.

When you’re on keto as a vegan, you aren’t eating the foods that naturally give you these nutrients because they come from animal products. Thus, you must deliberately add them in the form of supplements.

#8 You’re On Keto While Trying To Eat Low Fat

You already know I’m a passionate advocate of combining intermittent fasting with the keto diet. So, you’ve decided to eat keto - the only problem is, you’re trying to do it while eating low fat.

I know we’ve been bombarded with misinformation about the dangers of dietary fat, leading a lot of people to have the fatphobia. If this is you, you’re probably trying to keep all your dietary fat really low.

Here’s the problem with this.

If you keep both carbs and fat low, something has to increase. The only choice is to increase protein. And too much protein comes with its own problems.

As well, when you cut fats, you drastically lower the amount of fat-soluble vitamins and Omega 3 fatty acids that are essential for you to be healthy.

Correct These Mistakes And Keep Fasting

If you recognize that you’re making some of these intermittent fasting mistakes, I urge you to correct them. Not only will your health improve, but you’ll be setting yourself up for fasting success instead of fasting failure.

And I’m always in your corner, rooting for you to succeed.

Time for you to get the fasting benefits you deserve.

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Disclaimer: Our educational content is not meant or intended for medical advice or treatment.

Editor’s Note: This post has been updated for quality and relevancy.

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