Intermittent Fasting for Weight Loss

Intermittent Fasting for Weight Loss

The intermittent fasting (IF) trend for weight loss has caught on, and understandably so. It’s one of the most straightforward strategies for cutting back on weight.

You don’t need to buy any specially prepared, prepackaged smoothies or measure food proportions. You also don’t have to rack your brain, counting the calories in your meals. All you have to do is fast for a predetermined period. Put simply, it means you voluntarily abstain from eating for a couple of hours daily or on specific days of the week/month.

The benefits of intermittent fasting for weight loss are well-documented. This study that analyzed 27 IF-related trials found that individuals lost between 0.8 and 13% of their weight using this approach. But how exactly does this happen? Read on to learn more:

How Does Intermittent Fasting Work? 

Intermittent fasting helps you lose weight by breaking down fat and reducing your calorie intake. Sounds simple, right? Well, the science behind these two factors is a little more sophisticated than that.

To fully grasp how this happens, you should first understand how human metabolism works. So here’s a detailed breakdown of the basics:

The Human Metabolism

The human body needs a continuous supply of energy to keep all its systems functioning optimally. The primary source of energy comes from the food we eat. However, since we don’t eat throughout, a series of biological pathways kick into action to supply this energy between meals.

These pathways are always running in the background. However, the intensity of their involvement - in supplying energy - fluctuates once you’ve eaten. This fluctuation depends on an alternating cycle known as the feed/fast cycle

Feed is when your body has ample nutrients circulating through the bloodstream, typically after a meal. Conversely, the fast stage is when your body looks for alternative fuel sources after depleting glucose energy reserves

The feed/ fast cycle forms the basis of how intermittent fasting helps you lose weight by burning fat.

Feeding Cycle 

When you eat, the carbohydrates and fats cause a spike in blood glucose and lipid levels. This then triggers the production of insulin from the pancreas. This is the hormone that helps tissues throughout the body absorb glucose and lipids and convert them to energy. 

Now, it’s important to note that not all the glucose is used for energy production. The leftover is either stored in the liver as glycogen or converted to fatty acids and stored in fat tissues. 

Fasting Cycle

The body gradually transitions to the fast stage a couple of hours after eating. This begins with the blood glucose and lipid levels resuming normalcy. 

As a result, the tissues are forced to look for alternative energy sources to keep up with the supply. This is when they resort to the stored glycogen for fuel. 

The longer you fast, the more the body breaks down glycogen to supply energy. However, it reaches a point when even the glycogen reserves become depleted. Once this happens, the body breaks down fat into ketone bodies. 

The ketones - produced through a process known as metabolic ketosis - serve as the primary energy source. This remains the case until you break your fast.  

Calorie Reduction

Intermittent fasting is all about limiting your eating window. This technique requires you to choose a specific number of hours or days when you’ll refrain from eating. In doing so, you consume fewer calories, thus shedding a couple of pounds.

Depending on the intermittent fasting plan (more on this below), this fasting period can last between 12 and 40 hours. 

This doesn’t necessarily mean that you starve yourself the entire fasting period. You can drink water, coffee, and any other beverage that doesn’t contain calories. However, solid foods and calorie-rich drinks are entirely off-limits. 

For example, you can have dinner at 8 p.m., skip breakfast the next day and have lunch at noon. This translates to about a 16-hour fast. Some people prefer to fast from lunch to lunch, which equates to a 24-hour fast. Others prefer to fast for one or two days during the week. 

Whichever plan you choose, ensure you watch what you eat during the fasting period. Otherwise, your efforts to lose weight will be futile. 

Choosing Your Intermittent Fasting Plan

If you’re considering this weight-loss approach, there are several plans you can choose from. These include:

The 16/8 Schedule
The 16/8 method is one of the most popular time-restricted eating models. It means going a whopping 16 hours without eating, choosing to consolidate all your meals in the remaining 8-hour window. 

IF weight loss strategy prides itself on being extremely simple, and the 16/8 plan proves it. This is because individuals can pick any 8-hour timeframe that works for them. Do you prefer to fast during the day and eat at night? Or would you rather start fasting in the evening and break at dawn? Whatever you choose, roll with it. 

The 5:2 Schedule
With this approach, you get to follow your usual diet - calories included - five days a week. For the remaining two days, you must drastically reduce your calorie intake to a quarter of your daily needs. This translates to about 600 calories per day for men and just 500 calories for women. 

As in the previous case, you have total flexibility regarding scheduling. You can pick whichever two days you’d like to fast. 

Plus, there aren’t any hard and fast rules on what to eat for the remaining five days. Nonetheless, I would recommend that you watch what you eat. It’s pointless to fast for two days and then load up your body with calories for the remainder of the week. 

Another point to remember is the importance of spacing out your fasting days. This way, your body will have sufficient time to restore the essential nutrients it needs to function.   

Alternate-Day Fasting
Also known as the 4:3 IF plan, it entails fasting every other day. On the days when you’re not fasting, you’re free to follow your regular diet. 

There are two main variations of this fasting method. One involves eating a few calories on fasting days. However, the second one completely cuts them out. 

This is certainly a more extreme type of fasting, which is why it’s not recommended for everyone. It’s not suitable for people who suffer from certain medical conditions. It’s also not fit for individuals who are just getting started on intermittent fasting. 

But if you qualify, expect to get remarkable weight-loss results. One study found that the respondents lost up to 7.7 pounds of weight after following this IF plan for a month. 

The Warrior Diet
The Warrior diet emulates how our ancestors survived by means of hunting and gathering. This lifestyle forced them to spend long hours without eating anything, yet they still survived. As such, proponents of this IF plan believe that the human body can adapt to similar conditions. 

In this case, an individual eats minimally for 20 hours. They then eat one large meal, usually at night. During the 20-hour fast, they can eat raw veggies and fruits, tiny amounts of protein as well as drink natural juices, water, coffee, and tea. Once you break your fast, you can consume any nutrients in whatever amounts you prefer.  

Benefits of Intermittent Fasting

Why should you use intermittent fasting over other weight-loss strategies? If this question has crisscrossed your mind, here are some of the benefits it offers:


The biggest selling point of intermittent fasting is its simplicity. It’s less time-consuming and less taxing than the traditional calorie-counting method.

The best part, however, is that it doesn’t require any financial investment. Simply watch when and what you eat, and you’ll start losing weight within weeks. 

Secondary Health Perks

It’s a no-brainer that intermittent fasting helps with weight loss. But what many don’t know is that it has additional health benefits like:

  • Improving insulin sensitivity

  • Lowering the risk of heart disease and type 2 diabetes

  • Stabilizing blood glucose levels

Are There Any Risks?

If you’re considering this weight-loss approach, you’ll want to know the potential risks as well. These include:

Feeling Sickly

If you fast for an extended period, you may experience side effects, such as:

  • Irritability

  • Headaches

  • Fatigue

  • Constipation

In case this happens, shift to a more friendly IF plan. Specifically, look for one that allows you to eat some food every day. 

Risk of Overeating

Although your end goal is to shed a few pounds, you may end up gaining more. When you break your fast, your appetite hormones instantly go into overdrive mode to try and compensate. This means you’re more likely to overeat and indulge in other unhealthy habits that lead to weight gain. 

Not Suitable for Everyone

While effective, intermittent fasting isn’t for everyone. As stated earlier, some of these plans require you to cut back on your calorie intake for extended periods. 

This can be dangerous for people living with certain medical conditions, such as diabetes, heart disease, and high blood pressure. 


Intermittent fasting is a weight loss strategy that involves setting specific timeframes for eating and fasting. You can load up on any nutrients you like during your eating window. But when fasting, you have to abstain from solid foods and calorie-containing drinks.

This approach to weight reduction is revered for its simplicity and extra health benefits, including improved insulin sensitivity and a lower risk of heart disease.

There are many different types of intermittent fasting plans. This way, you can pick one that works for you and has minimal side effects.

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