7 Common Side Effects of Intermittent Fasting

Intermittent fasting is a practice that requires consistency and discipline, especially when its side effects want to get the best of you. A study found that headaches and lethargy are the two most common side effects of intermittent fasting, no surprise there. But, what are the other negative effects of fasting? And, more importantly, how do you deal with them?

Let’s explore the possible negative effects of intermittent fasting and how to prevent them.

Intermittent Fasting: A Quick Overview

Intermittent fasting consists of alternating between periods of eating and fasting. This change in eating patterns impacts the body’s physiological processes. Long periods of no food intake can potentially trigger survival mechanisms in the body, bringing positive effects with them.

Benefits of intermittent fasting include:

• promote weight loss

• improve insulin sensitivity

• help heart health

• reduce inflammation

• increase longevity

• boost brain function

7 Side Effects of Intermittent Fasting

The body will not be very receptive to a change in its routine, particularly meal-wise. A disruption in usual eating times can lead to multiple negative effects on the body. Let’s review the seven most common negative effects of intermittent fasting and how you can avoid them.

1. Hunger and Cravings

During the initial phase of fasting, you will experience hunger. But be strong! Feeling extreme hunger during fasting will only be for the first days as your body understands this schedule is the new normal. Stay on top of your fasting schedule using Fastic to help manage hunger and ensure you don’t miss those much-needed snacks.

Soothe hunger during fasting hours by drinking low-calorie, fruit-infused water and zero-calorie electrolyte beverages, or chewing zero-calorie gum. If you want to be a step ahead, aim for foods high in protein and fiber during eating windows to ensure you stay fuller for longer and throughout fasting hours.

2. Fatigue and Low Energy Levels

Reduced calorie intake and lower blood sugar levels during fasting can lead to fatigue because the body has fewer energy sources. Moreover, if your eating window is too short, you might not be getting the proper amount of essential vitamins and minerals, which can cause nutrient deficiencies.

A well-balanced, nutrient-dense diet is paramount for a healthy and triumphant fast. Ensure you eat the recommended calorie intake to guarantee your body has sufficient energy to perform everyday tasks during the fasting period.

3. Dehydration

Inadequate water intake can lead to dehydration. Besides the usual sweat and urination, the body may have lower water levels because of fewer meals. Fasting does not restrict you from drinking water during fasting hours, in fact, you should drink water regularly and even more than usual.

Maintain the recommended daily water intake during fasting using the Fastic app. The Fastic app can help you stay hydrated by sending you on-time alerts to sustain healthy water levels throughout the day. 

4. Headaches

Headaches during fasting are not uncommon, especially on the first days. The most common causes for getting a headache while fasting are low blood sugar levels, caffeine withdrawal, and fasting-induced stress.

To prevent fasting headaches, prepare your body and mind for the changes it will undergo. Gradually reduce your food intake as you approach the start of your fast. When you initiate the fast, don’t go straight into 20 hours of fasting, instead start with short fasting periods and progressively increase the duration.

5. Digestive Issues

Altering the body’s routine, both in diet and timing, can upset your stomach, leading to constipation, diarrhea, or nausea. Additionally, bloating during fasting may be due to overeating during eating windows, insufficient fiber intake, and eating bloating foods.

Save your stomach from an unpleasant experience by practicing mindful eating and eating slowly, planning nutrient-dense meals, particularly fiber-rich foods, and keeping track of foods you eat to help you determine what foods might be triggering digestive issues. 

6. Disrupted Sleep Patterns

Apart from a growling stomach in the middle of the night, fasting can also affect sleep due to changes in eating patterns. Disrupting a familiar routine can interfere with the body’s natural circadian rhythm, impacting the quality and quantity of your sleep. 

An easy tip to help you get adequate sleep is to adhere to a strict fasting schedule. Having a set schedule for meal times, fasting, and sleeping will help your body get used to the new program. To promote better sleep, avoid caffeine and screens before bedtime. 

7. Irritability and Mood Swings

Yes, you might feel hangry while fasting, and it's all due to physiological changes in the body. Less food intake means less glucose, the primary source of energy for the body and the brain to function, which puts the body under stress because it needs to look for alternative energy sources. An increase in cortisol levels, a stress hormone, can contribute to mood swings.

Manage these effects by practicing stress management techniques like meditation and deep breathing. Low to medium-intensity exercises can help distract your body and pump up endorphins. 

Side Effects of Intermittent Fasting in Females

Intermittent fasting can affect women in various ways, particularly due to its impact on the hormones that regulate the menstrual cycle.

Interfere with the menstruation cycle

Fasting can cause a hormonal imbalance in women. Fluctuation in hormones like estrogen and progesterone can lead to alterations and irregularities in the menstruation cycle. Additionally, changes in estrogen and progesterone levels can cause the following negative symptoms in women:

• headaches

• low sex drive

• hot flashes and night sweats

• acne

• hair loss

• dry skin

High levels of stress can negatively impact reproductive health in women. This happens when the hypothalamic-pituitary-adrenal (HPA) axis releases cortisol. Prolonged HPA axis activation can disrupt female reproductive hormones, delay ovulation, or temporarily cease it.

Slow down thyroid function

Long-term calorie restriction, whether through fasting or another dieting approach, can slow down thyroid function. Thyroid hormone imbalance can lead to hypothyroidism, which is known to be linked to fertility issues. Low levels of thyroid hormone can interfere with the release of an egg during ovulation.

Impact milk production 

Breastfeeding while fasting can interfere with the quality and quantity of milk. A study on lactating women undergoing fasting showed a change in milk synthesis, where osmolality, lactose, sodium, and potassium concentrations were negatively affected.

Despite the side effects of intermittent fasting in females, women can still enjoy a safe and effective fast while menstruating. Discover how to successfully balance fasting and your menstrual cycle, and avoid the potential side effects of fasting while on your period.

With a better understanding of the reasons behind fasting side effects, it's time to embrace the fasting experience. Download Fastic now to access a range of tools designed to help you minimize the negative effects of intermittent fasting. 

Disclaimer: It is advised to speak with a health professional before beginning intermittent fasting or a diet program. There may be side effects for people with certain medical conditions.