Is Intermittent Fasting Good for You?

Intermittent fasting has been on the rise for a variety of reasons. People on social media often suggest it by exaggerating its benefits. When more and more celebrities approve of this trendy diet, it becomes more convincing to the public that it is effective and healthy.

Although a ton of research has found intermittent fasting to be safe and effective, some studies provided evidence of its adverse effects. You might ask yourself, “Is intermittent fasting good then?” 

Throughout this article, you will learn the pros and cons of intermittent fasting that can help you decide whether to adopt this fasting diet.

What is intermittent fasting?

Intermittent fasting is an eating pattern involving alternating fasting and eating periods. While the literal definition of fasting is abstention from eating and drinking, you can still drink during the fasting. The importance is to choose drinks that don’t affect blood sugar or insulin levels, such as water and unsweetened coffee or tea. If you decide to do dry fasting, restricted from all foods and drinks, prepare yourself for dehydration.

Historically, fasting was done for religious or cultural purposes. For example, during the entire month of Ramadan, Muslims eat two times a day. They will have an early morning meal called suhoor before dawn and have dinner after sunset, known as iftar. Meanwhile, there will be no meal or drink during the day, similar to dry fasting practice.

Fasting is also part of Geneva culture, known as Jeûne genevois or “Fast of Geneva”. People celebrate the day of fasting in September to show penitence after tragedies such as wars, epidemics, or the plague. 

Fasting is now considered a weight loss regimen or healthy eating plan. The main rule is to limit the time range to consume food. In intermittent fasting, it has additional rules based on its type.

Types of intermittent fasting

There are several types of intermittent fasting, including time-restricted feeding, alternate-day fasting, and a 5:2 diet. Here are the following:

Time-restricted feeding

In this type of fasting, people can only eat during a certain period of time. The most common method is to fast for 16 hours and eat anything during an eight-hour window. 

During the fasting period, you can only consume zero-calorie beverages like water. However, research suggests that fasting for 12 hours is the safest option compared to fasting for a longer duration. 

Alternate-day fasting

Another type of intermittent fasting is alternate-day fasting. As the name indicates, it involves fasting every other day. 

You need to limit your calorie intake to 500 or around 20%-25% of your normal intake on fasting days. In a stricter version of alternate-day fasting, you can also opt not to consume anything during the day.

The Fast Diet

The 5:2 diet is also known as ‘The Fast Diet’ that was popularized by Michael Mosley. For this diet, you can eat normally for five days. Then, for two other non-consecutive days, you need to limit your calorie intake to 500 calories for women and 600 calories for men.

Benefits of intermittent fasting

Accumulating evidence indicates that intermittent fasting regimens are beneficial for weight loss and health. However, its effects vary from one person to another since everyone has a unique condition. The following are some benefits after at least one week of intermittent fasting:

Helps lose weight and belly fat

With the assumption that you don’t overeat during the non-fasting period, intermittent fasting will enhance hormone function to facilitate weight loss. One of the mechanisms is by influencing the ghrelin system. Also known as the hunger hormone, ghrelin is a hormone that stimulates appetite. During fasting, the high production of ghrelin will send signals to your brain, leading you to experience food cravings. After an extended period of intermittent fasting, the ghrelin levels will decrease. You will eventually feel less hungry, hence, you will eat less.

Moreover, the changes in the metabolic rate encourage the body to burn fat instead of relying on the constant supply of glucose to create energy. It is estimated that people may lose around 0.25 kg – 0.75 kg per week

Fasting will also result in belly fat loss. Studies also showed that people experience a reduction of 4%–7% in waist circumference after 6–24 weeks of adopting intermittent fasting.

Intermittent fasting can manipulate both sides of the calorie equation. It reduces calorie intake and increases calorie expenditure by boosting the metabolic rate, which explains this effect.

Helps fight inflammation

According to a study, people eat snacks 2 to 3 times daily, most frequently between 3 and 8 PM. These snacking behaviors can increase calorie intake, while sedentary behaviors will further decrease calorie expenditure. Once people adopt this lifestyle, it is easy for them to gain fat.

As a natural response against foreign organisms, inflammation can also happen due to fat from excess calorie intake. The accumulation of fat then releases proinflammatory molecules eliciting a low-grade inflammatory reaction. Over time, it increases the risk of various diseases, including metabolic syndrome, type 2 Diabetes Mellitus, and cardiovascular diseases. Regulating calorie intake and expenditure is hence essential in fighting inflammation. 

Studies recommended a low-calorie diet, such as intermittent fasting, to manage balanced calories. Through molecular mechanisms called autophagy, fasting reduces the production of proinflammatory molecules, suppressing chronic inflammation. Instead, the body promotes cell repair and rejuvenation, further reducing the risk of inflammation.

Helps improve brain function

Since inflammation can also damage neurons, it can lead to cognitive function impairment and brain disorders development (e.g., Alzheimer’s disease, Parkinson’s disease, and depression). The mechanism of autophagy provoked by a fasting diet also benefits brain function. 

Moreover, fasting will not only reduce inflammation but also generate new neurons, also known as neurogenesis. Intermittent fasting has been shown to increase the production of brain-derived neurotrophic factor (BDNF). It is a protein that plays a crucial role in promoting neurogenesis and supporting the survival of existing neurons. With rejuvenated neurons, brain functions improve, including attention, working memory, and executive function. In addition, the brain will become less vulnerable to age-related decline and neurodegenerative diseases. 

Apart from reducing inflammation and producing BDNF, you can improve your brain function by consuming foods that keep your brain healthy. While it has been said that intermittent fasting is about when to eat rather than what to eat, you can optimize this diet by paying attention to the type of food you consume. For example, plant-based foods like leafy vegetables may help slow cognitive decline.

Read more: Foods That Keep Your Brain Healthy 

Potential side effects 

Intermittent fasting may be suitable for some people but not others, particularly for individuals with certain medical conditions or who are pregnant. Considering potential pitfalls before starting new diet plans is always a good idea. While an intermittent fasting diet offers some health benefits, as mentioned above, it may also have potential side effects such as:

Digestive issues

The changes in your diet can alter the gut microbiome and digestive function. You might experience symptoms of digestive issues like diarrhea and constipation when you do intermittent fasting. Moreover, what you eat during the feeding window will affect the symptoms that you experience. 

When you eat greasy and fatty foods, the trans fat will be broken down in the large intestine, causing the release of extra fluids. When you eat spicy foods, capsaicin can irritate the intestines. When you drink coffee, caffeine may stimulate your digestive system. The interesting part is when you eat a large amount of high-fiber foods (e.g., beans, whole grains, and avocado), which although essential for your health, can also lead to diarrhea.

On the other hand, low-fiber foods will limit your bowel movements resulting in constipation. Moreover, intermittent fasting can cause dehydration which can worsen constipation. 

To avoid these digestive problems, you need to listen to your body and adjust your diet accordingly. The key is maintaining a balanced diet with appropriate fiber, protein, healthy fats, vitamins, and minerals.

Read more: The Perks of Having a Balanced Diet 


When you limit your energy intake, you will have low blood sugar during fasting. It makes you feel more tired and weaker than usual. However, as your body adapts to this new regimen, you might no longer feel tired during fasting.

Consider gradually adjusting your fasting schedule when you just start implementing the diet plan. It will give your body some time to adapt to the fasting practice fully. Then, you may even feel more energized since your body becomes more efficient in mobilizing the energy reserves. 

In some cases, intermittent fasting can cause sleep disturbances which could tire you even more and impact your productivity. A preventive measure you can take is to ensure you are getting adequate sleep. Maintaining a consistent sleep schedule, creating a relaxing sleep environment, and avoiding stimulating activities before bedtime could reduce the risk of sleep disturbances. It will also help you conserve your energy for daily activities.

Read more: The Impact of Sleep on Productivity and How to Get Better Sleep 


If you don’t plan your fasting program carefully or restrict your calorie intake excessively over an extended period, it could result in malnutrition. 

Malnutrition is an imbalance between your nutrient needs and nutrient intake. It generally covers two broad categories: undernutrition and overnutrition. Undernutrition occurs when you don’t have enough nutrients, whereas overnutrition is when you have too much.

Since you limit your intake during intermittent fasting, you may experience undernutrition. You either lack the overall calories or have a mineral and vitamin deficiency.

A decrease in the sense of smell and taste, along with symptoms such as diarrhea and brittle hair, could be indicators of zinc deficiency. Ignoring these signs and maintaining a zinc-deficient diet could result in difficulties with conception, primarily since this deficiency is known to cause impotence in men. To address this issue, it is recommended that you increase your zinc intake by incorporating more zinc-rich foods, such as red meat, peas, and almonds, into your diet.

Another possible scenario is vitamin D deficiency, which could present with symptoms such as hair loss, lower back pain, and irregular menstrual cycles for women. 

Meanwhile, vitamin B12 deficiency can make you anemic, have pale skin, or experience nerve problems such as numbness.

To meet the right amounts of nutrients during intermittent fasting, you need to adjust your meal plan or take some supplements. For people with certain conditions, seeking a healthcare professional’s advice before practicing intermittent fasting would be recommended.

In conclusion

Many diet regimens are being promoted on social media, including intermittent fasting. Its benefits are often exaggerated, whereas its risks are downplayed. 

When you practice intermittent fasting correctly, you may successfully lose weight, reduce the risk of inflammation, and enhance your brain function. 

However, you should also note that you may experience digestive issues, tiredness, and malnutrition if you don’t carefully plan your calorie and nutrient intake during the feeding period. If you want to give intermittent fasting a try, it’s suggested to consult with your doctor first.

If you would like to see more resources on malnutrition, check out the Personal Resilience Science Labs. The lab uses the research of the Institute for Life Management Science Labs to produce courses, certifications, podcasts, videos, and other tools. Visit the Personal Resilience Science Labs today.

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