Intermittent fasting has shown major breakthroughs when it comes to weight loss and many are living testaments to how fast and effective its results are.

However, as with any other diet plan, particularly one as rigorous and strict as IF, it may come with some side effects. Before starting on your intermittent fasting journey, you have to understand how it affects your body and what ill effects it may bring so you can prevent them from happening or are prepared with the right interventions when they do happen.

Intermittent fasting has a bad side, but for many people who have succeeded with it, these side effects can also be manageable and surmountable. Here are seven IF side effects that you should watch out for.

1. Hunger and cravings

Because you are given only a small window to eat, expect to feel hungry and be more tempted to give in to cravings throughout the rest of the fasting period. This is especially challenging if you’re on the hardcore 20:4 or challenging 16:8 diet, though experts say that you should include your sleeping time to the fast period so you have fewer waking hours. If you need to fill your stomach, you may instead drink plain iced tea, water or black coffee.

2. Feeling overly full after eating

Because your body is so used to not eating for the most part of the day, you might feel uncomfortable by the time you do get to have your major meal. At times, you will be constipated and feel bloated. Scheduling your eating window at night can also lead to poor quality of sleep.

3. Heartburn

Most people who practice intermittent fasting identify heartburn as a common side effect. Usually, this fixes itself in about two months, but if it doesn’t you should go see your physician. Heartburn happens because your body was used to your eating pattern and would automatically release stomach acids at specific times. It will eventually stop when your body adjusts to the new habit, but it can be very uncomfortable at the start.

4. Being too reliant on teas and coffees

Because you can’t eat during the fasting period, you might become too reliant on coffees and teas. However, it can also lead to dependence. Drinking too much coffee or tea can also wreak havoc on your sleep quality and cause anxiety and stress, which will then result in rebound weight gain.

5. Headaches

Headaches are a common side effect of IF because the body is used to having food in the stomach. Some intermittent fasting practitioners experience it once in a while, while others have throughout the entire course of the program. The quick fix is to drink enough water, but if the headaches are persistent, it’s best consult with a health advisor or doctor.

6. Brain fog

People on IF, especially those new to it, often experience brain fog. This side effect happens because the body is not used to not eating and so the mind will try to keep up, thereby causing some confusion or periods where it seems you’re blanking out or being forgetful. Over the long term, however, there are studies that say intermittent fasting can help boost brain function.

7. Low energy

This is one of the top side effects of intermittent fasting. Because you don’t eat, you naturally feel weak and have low energy, which can stop you from being physically active. Some people tend to become irritable, even.

Overall, the long-term beneficial and side effects of intermittent fasting are still unknown, that’s why it is not recommended to be practiced for years. When you have reached your desired weight, try to adjust your fasting schedule and bring in physical activity to your regimen, so that you don’t always have to watch the clock. In the long run, the key to losing weight is really to have a balance diet and engage in exercise.

Weight Loss Diet
Here are seven IF side effects that you should watch out for. Pictured: Youths eat a healthy lunch at a slimming center in Beijing Getty Images/Liu Jin