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I would like to preface this article by stating that I am not a qualified dietician or a doctor of any sort, so what I mention in this article is just what knowledge I have gained throughout my life about what is Intermittent Fasting.1
1. What Exactly is Intermittent Fasting?
In a few words, Intermittent fasting is best described as a diet (for weight loss) in which one only, strictly eats in the “Eating window” and doesn’t have any calorie intake in the “Fasting Period”. This leads to a caloric restriction in the body.
The fasting period can last from 12 hours to up to 40 hours. During these fasting periods, one can have calorie-free drinks such as black coffee or tea but not any solid food items or anything with calories in them.

It has gained popularity as a method of fasting for weight loss in the past years, yet it may not be the diet for everyone. One size does not fit all.
2. Ways to Do Intermittent Fasting
- Time-restricted feeding- This involves fasting for 12 hours or longer and saving the rest of your hours for eating. One of the most common methods is the 16/8 method, in which you fast for sixteen hours and eat in the rest and can easily fit two meals in that. You can skip breakfast and eat your lunch around noon to start.
- 5:2 Diet- In this, you eat normally for 5 days of the week. On the remaining two days, you restrict your calorie intake (i.e. have less calorie-fueled food than you usually have).
- Eat-Stop-Eat: Another intermittent fasting plan includes fasting once or twice for 24 hours a week. Not for me.
- Alternate day fasting plan- Yes, you’ll have to fast every other day of the week.
- Warrior diet- In this, you only eat raw vegetables and fruits during the day and you end the day with a heavy protein-loaded meal.
While it may be tempting to try the hours thinking that it’ll be more effective but it actually can cause more damage than good.
3. The Science of It All
To put it simply, our body needs energy. From where do we get this energy? By utilizing our sugar stores aka glucose.
So when our body undergoes long periods of fasting and is out of sugar to burn for energy, it has to find other sources of energy. Now, it starts burning up your fat reservoir. This phenomenon is also referred to as “Metabolic Switching2” (a term given by Mark Mattson).

Mark Mattson has worked extensively on intermittent fasting and he hypothesizes that during fasting, the cells of our body respond to this stress in the same way it responds to the stress from exercise.
However, fasting for too long has a counter effect and leads to increased fat stores in response to excessive starvation.
4. The Health Benefits of Intermittent Fasting
- Supports weight loss: One of the main reasons anyone tries intermittent fasting is because they want to lose weight and lead a healthier lifestyle. It increases your metabolic health, which can be defined as how well your body processes food for energy. Our body composition changes in a good way. The 16/8, along with the alternate day fasting, are some of the types of intermittent fasting that have been linked directly to weight loss. Intermittent fasting also helps in regulating your appetite such that you don’t feel hungry and reduce your meal sizes/frequency.
4.1 So How Does Intermittent Fasting Help with Weight Loss
- It’s simple. By eating less, you are creating a calorie deficit. Now that you don’t have a particular amount of calories needed to maintain your current weight, you lose that weight. When the body uses fats to make energy, it produces ketone bodies. These substances, plus the fewer calories in the diet, aid in weight loss.
- Apart from losing weight, it also helps with maintaining other associated risks, such as- Lowering your blood pressure, improving blood sugar regulation, and repairing damaged cells.
- Complementary nature of it- You don’t necessarily need fancy exotic ingredients to make some god-forsaken smoothie or salad in this type of diet, you can eat your regular meals and follow a normal diet without any need to buy something extra.
- For people with chronic diseases such as Type 2 Diabetes- It is a godsend for patients suffering from type 2 Diabetes. Research suggests that intermittent fasting (fewer calories) reduces the blood sugar level (glucose level), fasting insulin, and leptin while reducing insulin resistance and increasing levels of adiponectin. Intermittent Fasting has been shown to result in improved insulin sensitivity which is basically how well our cells respond to the effects of insulin telling cells to remove glucose from the blood.

5. The Research Behind the Science
Most of the research related to intermittent fasting has been on animal models, rather than human studies.
Additionally, according to a review conducted by the JAMA Network of the meta-analysis of the randomized controlled trials of intermittent fasting and its correlation to weight loss, only 6 out of 104 of the health benefits were supported by moderate to high-quality evidence. Most of the research work was also of low quality.
6. For Whom This is Not the Diet
So now we know the bracket of people for whom this diet may work. Let’s discuss the people for whom this diet will not be helpful.
So first off, we have children and teenagers below the age of 18. There’ll be no need for kids to diet (except in extreme cases, in which case it is best to consult doctors before going on any diet). Eat and let eat. During your teenage years, your body undergoes puberty and so many other hormonal changes. It is best to give your body to acclimatize before jumping to follow any diet.
Next, women who are carrying a child or breastfeeding should preferably not start intermittent fasting. Pregnant women have to be eating for two, not one-half. Skipping meals3 is not the ideal thing to do when a child is growing inside you. Depriving themselves of any slight nutrient could prove to be detrimental to their child’s growth. To prevent any mishappenings, expecting mothers are advised not to try intermittent fasting. However, starting IF after the breastfeeding phase is over is acceptable and poses no risks.
Third on this list is probably the most vulnerable in this group- people with eating disorders. Throughout history and with the popularity of the ‘if thin, then pretty’ culture, people have tried so hard to mold themselves into perfect little dolls for a world that won’t even give them the time of their day. It can be arduous to get over disordered eating and if you won that battle, I commend you for that, but trying intermittent fasting could lead you back to that battlefield. Skipping meals could prove to be so detrimental to all the progress they’ve made so far.
7. The Negatives
There can be some negative effects of intermittent fasting eating patterns-
- Increased appetite leading to bingeing
- lethargy
- negative mood
- increases irritability
- disordered eating
- obsessing over food and calories
8. Alternatives to Intermittent fasting
There are a couple of more diets that you could try before seeing which works best for you as everybody functions in a slightly different way, and only you can make this decision in the end.
Mediterranean Diet– The major benefit of this diet over intermittent fasting is that it has the advantages of intermittent fasting without the fasting bit of it. So basically, this diet is inspired by the eating pattern of the people of the Mediterranean basin. You can eat breakfast on this diet.

Apart from preventing the risk of heart attacks by 30% if followed for a long period, this diet has also been shown to be helpful against colorectal cancer and against loss of nerve cells (which happens in Parkinson’s disease)
Calorie Restriction Diet- This diet is all about smaller portion sizes and hence lower calories. The benefits of both intermittent fasting and calorie restriction diets are comparable. Though it has been suggested that intermittent fasting may be more sustainable than calorie-restriction diets in the long run.
9. Conclusion
There are only two things that can happen once you decide to try intermittent fasting, it either works for you and causes a positive lifestyle change, or it doesn’t work for you. To reach the question of whether it works for you, it is crucial to try it out in the right manner. Eat nutrient-rich food during the eating periods and avoid processed food. In the end, you need to realize that this is just another weight loss tool, one of many weight loss methods. Do consult your healthcare team for better advice, of course. The bottom line of it all is having a healthy diet and having balanced meals, and restricting calories that you don’t need. The line between food deprivation and healthy fasting has to be not crossed.
10. Frequently Asked Questions (FAQs)
1. How do you do intermittent fasting?
The way to “do” intermittent fasting is to follow a pattern of a “Fasting” phase and an “Eating” period. You fast for about a minimum of 12 hours and can eat the normal meals you typically eat in the eating window. The aim is to reduce the total amount of calories consumed. These meals obviously cannot be heart attacks disguised as meals. It is preferable to eat food that has higher nutrient content (for example, vegetables and lean protein)
2. What exactly happens in intermittent fasting?
So, glucose is what our body utilizes to gain energy and function normally. When we deprive our bodies of the set amount of glucose (in the case of fasting), our cells start using up the fat stores and burn fat for energy. This is a good thing. Our fat is burning up, which ultimately leads to weight loss.
3. Does 12 hours count as intermittent fasting?
Yes, the 12:12 pattern is the intermittent fasting pattern that most people begin with. It’s the place to start if you’re new to this whole thing. You fast for 12 hours (typically skipping breakfast) and are allowed to eat for 12 hours.
4. How long should you do intermittent fasting?
Anything from 10-16 hours is good enough to encourage weight loss of course, with varying intensities depending on the number of hours you’ve fasted.
As to the question of how long one should follow this diet, it should be for long as you feel the need to or see the results you wanted to achieve.
- Liu, Kai, Bo Liu, and Leonie K. Heilbronn. “Intermittent fasting: what questions should we be asking?.” Physiology & behavior 218 (2020): 112827. ↩︎
- Mattson, Mark P., et al. “Intermittent metabolic switching, neuroplasticity and brain health.” Nature Reviews Neuroscience 19.2 (2018): 81-94. ↩︎
- Pendergast, Felicity J., et al. “Correlates of meal skipping in young adults: a systematic review.” International Journal of Behavioral Nutrition and Physical Activity 13 (2016): 1-15. ↩︎
Last Updated on by Sathi