Intermittent fasting is one of the more popular weight-loss strategies over the past several years. As more people try intermittent fasting for the first time, many have faced roadblocks or other problems while trying to fast. Let’s look at some of the most common intermittent fasting mistakes.

What constitutes an “intermittent fasting mistake”?

Intermittent fasting mistakes are anything that:

• Impedes your ability to adhere to your fasting schedule
• Impairs your ability to function in the basic duties of your life
• Physically harms you, even in a minor way
• Causes fasting to work less effectively

Avoiding any of these mistakes is critical to having success with fasting, whether you’re trying to lose weight or improve your health. Let’s look at the specifics of the worst intermittent fasting mistakes you can make.

Focusing solely on the fasting window

Some people focus too much on the fasting aspect of IF, ignoring the importance of their eating window. It is crucial to maintain a balanced and nutrient-dense diet during your eating periods to support your body’s needs. Consuming adequate amounts of protein, healthy fats, vitamins, and minerals is vital to maintain energy levels, supporting muscle growth, and preventing nutrient deficiencies.

Not planning your eating and fasting time

It’s perfectly fine to start your fast right now if you’re considering giving intermittent fasting a try. Simply finish whatever you’re eating and commit to not eating for the next 16 hours. 

The problem people have is that once they’ve gotten into a habit of fasting, they vary their eating schedule too widely. For instance, most people do best when they stop eating after dinner – around 8 pm – and skip breakfast the next day, resuming their eating time at noon. This is a simple, 16-hour fast and it works very well.

If you vary these times too much, however, you end up voraciously hungry and potentially non-compliant on your fast. If you eat until midnight, for instance, you can’t eat until 4 pm the next day, and the chances of you lasting that long are dramatically lower than were you fasting from 8 pm to 12 noon the next day. By not planning out when you stop and start eating, you open yourself up to failure.

You don’t take electrolytes while fasting

One of the biggest hurdles to fasting for most people is the drop in energy you might experience as your body transitions from carbohydrate-based to fat and ketone-based for energy. As you fast, your body depletes blood sugar and then the stored form of blood sugar, called glycogen. Since glycogen is stored in your liver and muscles within water this depletion of glycogen causes you to get rid of a lot of that stored water. While this drop in water weight causes rapid weight loss, the loss of water also flushes sodium, potassium, and magnesium from your body.

This means you need to be drinking electrolytes during your fast in the least caloric way possible. Magnesium glycinate tabs, around 250 mg, will help you maintain your magnesium levels. Potassium can be replenished with 1/8th tsp of cream of tartar in water, and sodium is easy to get from salted bone broth.

You should also be eating electrolyte-dense foods when in your feasting window. These include:

• Dark, leafy greens
• Salt
• Avocado
• Walnuts
• Salmon and other cold-water, oily fish like sardines
• Pumpkin seeds
• Broccoli
• Plain, full-fat Greek yogurt

Without proper electrolytes, you’ll have muscle cramps, fatigue, headaches, and irritability, among other problems. The good news is you can easily prevent these problems by staying on top of your electrolyte intake.

This intermittent fasting mistake is especially true if you’re exercising while fasting. During one particularly strenuous weight lifting session, I came out of the squat rack, having fasted for 18 hours. While the length of the fast wasn’t remarkable for me, the blood pressure drop from squatting and standing was. I ended up face-down on the gym floor with my trainer freaking out, and after that, I added a pinch of salt to all my bottles of water; problem solved.

Getting too few calories after fasting

One of the biggest intermittent fasting mistakes made is that some people don’t eat enough during their feasting window. We’re not saying you should gorge yourself, but you need to make sure you’re getting enough nutrient-dense food to sustain your body. If you break your fast with white bread and chips, you’re going to pay the price a few days later as your energy starts to diminish. 

A calorie calculator can help determine your exact caloric needs based on gender, age, weight, height, and physical activity level. A quick and simple method to determine your daily calorie needs, however, is to multiply your current weight by 10. This will give you a broad estimation of the upper limit of your calorie needs to maintain your current weight.

For weight loss, don’t reduce your daily calories by more than 500 calories under your daily caloric requirements. If you want to figure out your daily calorie requirements (basal metabolic rate) use our handy BMR calculator.

Getting too many calories

This is a no-brainer, but many people break their fasts with a real feast, and this intermittent fasting mistake will stall and stymie your weight loss efforts. What’s worse, if you break your fast with high-sugar foods, it can damage your cardiovascular system. ¹ Use fasting as a way to reset the way you eat and your relationship with food, and learn to love whole foods made from plants and animals; the less processed your food is, the better.

Breaking your fast with too much food too quickly

At about 14 hours of fasting, digestive enzymes are very low ² and the act of digestion slows down dramatically. If you introduce too much food too quickly, you will end up with a stomach ache in most cases. It can also cause heartburn and nausea. For those who do longer fasts, refeeding too quickly can trigger the gastrocolic effect. Suffice to say, you’ll want to be near a bathroom in those cases.

Refeeding should begin with a very small amount of food, and ideally something easy to digest. Soup is a good choice, as are a few nuts, berries, or gelatin. Then, after about an hour, you should be able to eat normally.

Ignoring your body’s signals

Another intermittent fasting mistake is not realizing that everyone’s body is different, and the way it responds to intermittent fasting can vary. Pay attention to how your body reacts to the fasting protocol you have chosen. If you experience extreme fatigue, dizziness, or other adverse symptoms, it might be a sign that the fasting method is not suitable for you. Consult your healthcare professional for guidance on adjusting your intermittent fasting plan or exploring alternative approaches.

Not being consistent

Consistency is key for any health or weight loss plan, including intermittent fasting. Some people may give up too soon or not follow their fasting schedule consistently, which can hinder their progress. It is essential to give your body time to adjust to the new eating pattern and stick to the plan as consistently as possible. Remember that progress may be slow, and it’s crucial to be patient and persistent.

Not having a meal plan in place

When you first ingest food after your fast, your body will ramp up ghrelin production, ³ which is the hunger hormone. If you don’t have a healthy meal planned, you are far more likely to gorge yourself on whatever easily accessible food is lying around, including junk food. While it’s true that any diet is made easier through meal planning, fasting, in particular, can cause you to eat ravenously and so extra care should be taken to eat sensibly during your feasting window.

1. www.ncbi.nlm.nih.gov/pmc/articles/PMC2585377/[↩]
2. www.ncbi.nlm.nih.gov/pmc/articles/PMC5767472/[↩]
3. www.ncbi.nlm.nih.gov/pmc/articles/PMC4049314/[↩]