How to do intermittent fasting for serious weight loss

How to do intermittent fasting for serious weight loss
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Ever since I’ve tried it, intermittent fasting (or IF) has quickly become one of my go-to ways whenever I need to lose weight. As effective as it is, it’s probably even easier to understand especially when you strip it down to its basics.

Seriously, it’s not that complicated. However, there are a few key things you probably want to know about so you yourself can learn how to do intermittent fasting for serious weight loss. 

This article is going to talk about all those key things, including how it works, its benefits, the different types of intermittent fasting, and how you can successfully pair it with other weight loss techniques. 

Let’s get to it! 

How does intermittent fasting work for weight loss?

In layman’s terms, intermittent fasting works as an effective tool for weight loss because it discourages overeating. And, with less food, you ingest less calories which leads to weight loss. 

In more scientific terms, however, intermittent fasting does its magic through our hunger hormones —  insulin, ghrelin, and leptin to be more specific — which in turn affects how we metabolize energy.

Speaking of energy, we get that from the food we eat in the form of glucose. Carbs are our body’s main and preferred source but parts of protein and fat are converted into glucose as well. 

Now, when you have glucose in your bloodstream, your body releases insulin as a response. 

Insulin helps your body store that glucose either in your muscles where they can be used immediately or in your liver where they’re stored as energy reserves also known as glycogen. When both your muscles and liver are full, your body then moves on to storing excess glucose as fat. 

With that said, research also says that insulin reduces the amount of ghrelin (the hunger hormone) while simultaneously increasing levels of leptin (the satiety hormone) which, ultimately, makes you feel full and satisfied. 

This hormonal cascade is largely why intermittent fasting is so great for weight loss but it doesn’t tell the whole story. 

Theoretically, the prolonged fasting period of IF deprives your body of a regular source of glucose, forcing it to tap into your glycogen stores. When that runs out as well, your body turns to burning fat for fuel (sort of like the ketogenic diet which we will also discuss later on). 

So, aside from weight loss… 

What are the benefits of intermittent fasting? 

All in all, intermittent fasting shares a lot of the same benefits as most other diets. These include:

  • Decrease in levels of total cholesterol
  • Reduced levels of “bad” cholesterol
  • Lower levels of triglycerides
  • Decreased levels of both insulin and blood sugar
  • Better blood pressure

Also, evidence suggests that improving the above levels also coincides with improved levels of inflammation. Ultimately, all of these are going to help steer you away from chronic diseases like diabetes, heart disease, rheumatoid arthritis, cancer, and several others. 

However, one study does say that because these effects are similar to other diets, the benefits of intermittent fasting stem largely from its effectiveness as a weight loss agent. 

Whatever the reason is though, I personally believe that the best thing about intermittent fasting is its simplicity. 

So, here’s how you do it right:

How to do intermittent fasting correctly

Unlike most other diets with all their restrictions and how they tell you to only eat certain types of food, intermittent fasting isn’t all that complicated. The only basic intermittent fasting rules you should remember are: 

  • Don’t consume too many calories, if any during your fasting period, and
  • Eat most, if not all of your nutrients during your feeding window

Of course, there are a few other auxiliary rules to follow when you want to lose weight (we’ll talk more about this later) but those apply to generally any diet. 

Also, if you were asking “how many hours should you do intermittent fasting to lose weight?” and “how many meals can you eat while intermittent fasting?”, it all depends on what style of intermittent fasting you choose to do. 

Each type also has its share of specific rules, so pick one that you think is most comfortable to you. 

Here are your choices: 

The different types of intermittent fasting:

All in all, there’s 7 popular intermittent fasting schedules you can choose from. They all have different fasting patterns where some use hours, some use days, and some others use meals. 

Let me start you off with types that have an hourly fast-feast pattern. 

The 12:12 method

Otherwise known as overnight fasting, the 12:12 method will have you fasting for 12 hours and eating for the other 12. Meaning, if you stopped eating 8 PM, you can eat again at 8 AM the next day. 

Many people, including myself, consider this the most beginner-friendly type of intermittent fasting because if you time it right, sleep does most of the fasting for you. 

16:8 intermittent fasting

With 16:8, you fast for 16 hours and have an 8-hour eating window. For example, you start eating from 12 noon until 8 PM and abstain from food for the rest of the day. 

This is a slightly harder fasting method than 12:12 but still relatively easy to do. 

I personally prefer this method because it fits my schedule. I simply skip breakfast, eat a heavy lunch, a lighter dinner, and maybe a couple of healthy snacks in between. 

If you don’t want to skip breakfast, that’s fine. You could also eat your breakfast at 8 AM, have lunch as you normally would at noon, and have your dinner early at 4 PM. If this is what you prefer, I suggest eating foods that suppress your appetite for dinner to help keep you full until you can eat again the next morning. 

The Warrior Diet (20:4 method)

This version involves fasting for 20 hours and having a 4-hour eating window. Thus, why it’s sometimes referred to as the 20:4 method. 

It’s supposedly based on how warriors/hunters ate very little during the day as they performed their duties and feasted at night after they’re done. 

I kid you not, I once tried this version of intermittent fasting because I wanted to feel like a part of King Leonidas’ army in the movie 300. I don’t know how to wield a sword and my neighbors would think I was crazy if I shouted some sort of battle cry, so I tried the warrior diet instead. (Cue Gerard Butler screaming “Tonight, we dine in hell!”)

What I did was I ate my day’s worth of food from 4-8 PM, slept, skipped the next day’s breakfast, lunch, and everything in between, then started eating again at 4-8 PM the next day. Of course, you can adjust your 4-hour eating window to fit your own schedule. 

The 5:2 method of fasting

The 5:2 method is a little different since you won’t be counting hours. Instead, you get to eat for 5 days and fast for 2. 

Generally, the 5-day eating window is where you can eat “normally”. But if, to you, normal means clearing out the junk food aisle and eating fast food for all your meals, you might want to consider changing your habits. You might lose a bit of weight this way but it’s not going to be healthy nor sustainable. 

Also, the 2-day fast of the 5:2 method allows you to eat a quarter of your normal intake. So, if you typically ate 2000 calories per day, for example, you’d have to limit your food intake to 500 calories on your abstinence days. 

Granted, a quarter of your normal calories isn’t a lot but at least you still get to eat food. 

Eat-stop-eat

I see eat-stop-eat as a similar method to 5:2 where you fast for 24 hours once or twice a week. The difference is that eat-stop-eat prohibits you from consuming any calories for a full 24 hours whereas you’re allowed to consume a few calories with 5:2. This makes the former slightly harder to follow but it’s still very doable. 

Why?

Because fasting for 24 hours doesn’t necessarily mean you can’t eat anything for a full day. For example: 

  • You start fasting at 12 noon on Monday.
      • This gives you enough time to have an early lunch and an on-schedule breakfast. 
  • You end your fast at 12 noon on Tuesday. 
    • This gives you a full 24-hour fast and enough of a window to eat a late lunch and a normal-time dinner.  

Of course, feel free to adjust. You can fast breakfast-to-breakfast or dinner-to-dinner if you think it better fits your schedule. 

In any case, I advise you not to line up your fast days consecutively for both the eat-stop-eat and 5:2 methods. Instead, give yourself 2-3 full days of eating between each fast. I believe this makes it easier to follow and more sustainable long-term. 

Here’s a sample weekly schedule you can reference to and adjust as needed: 

Monday Fast
Tuesday Eat
Wednesday Eat
Thursday Eat
Friday Fast
Saturday Eat
Sunday Eat

Occasionally skipping meals

Along with 12:12 and 16:8, I think this is right up there with the easiest IF methods to follow. 

It’s great for beginners because it’s literally just skipping meals from time to time. There’s no actual structure to it either, so you don’t have to pick a specific meal or day to do your fast. Just do it when you don’t feel as hungry or if you feel like you can do without food during that certain time. 

Don’t feel as hungry for dinner? Skip it. Way too busy to make breakfast today? Skip it. 

Perhaps the only other guideline you should follow here is to aim for at least 1 to 2 skipped meals every week. 

Alternate-day fasting (ADF)

At its very core, ADF is just fasting every other day. However, it does come with a few different names and sub-variations. 

For example, a more extreme way to do this is to not consume any type of calories on your fasting days. You could also consume 25% of your usual daily calories, or consume 500 calories regardless of what you deem normal. 

Whatever route you go with though, the end result should be consuming significantly less calories for the whole week, leading to weight loss. 

This brings us to the next question: 

Which intermittent fasting method is best for losing weight?

In terms of consuming the least amount of calories, alternate-day fasting seems to have the most potential for weight loss, particularly if you chose not to eat anything on your fasting days.

Granted you consumed your normal amount of calories during your eating days, this version of ADF essentially cuts your weekly caloric intake in half, leading to rapid weight loss. And, even if you did eat a few calories on your fast, you’d still be cutting your overall intake several folds. 

However, this drastic cut in both weight and calories also means that it’s not sustainable for most people. Per the CDC, a healthy weight loss means only losing 1-2 lbs per week — and you’d likely lose more than that with ADF. Plus, it’s one of the harder ones to do. 

That being said, I think the best intermittent fasting method for losing weight is one that gets you gradual yet sustainable weight loss results while also being relatively easy

In my eyes, 12:12, 16:8, 5:2, and spontaneously skipping meals fit the bill, so maybe try to experiment with those first. 

And while we’re on the topic of sustainability…

Can you do intermittent fasting long term?

Short answer: Yeah. Probably. 

But here comes the long answer and why it’s a little complicated:

Per Dr. Donald Hensrud of the MayoClinic, there’s very little research done on the long-term effects of intermittent fasting. I checked and true enough, I barely found anything. Hence, we can’t really look too far ahead into the future here. 

From what I gather, however, the issues behind the long-term repercussions of intermittent fasting lies in how some of the methods require extremely low calories. We don’t need any more research to prove how that’s both unhealthy and unsustainable. 

Another issue is the assumption that IF dieters can eat anything and how ever much of it they want on their non-fasting hours. This can lead to malnutrition — and, again, that’s both unhealthy and unsustainable.

The fix?

In the hours where you feed, have the presence of mind to:

Let’s get more into detail, shall we? 

How to maximize intermittent fasting results

First, let’s talk about portion control. 

Per the MayoClinic, you should generally cut 500-1000 calories per day to achieve a healthy weight loss. 

Considering how some intermittent fasting methods will have you eating little to no calories on certain days, however, just aim for the weekly equivalent of eating 500-1000 fewer calories per day. That’s 3500-7000 fewer calories at the end of each week. 

That much should still get you losing the safe 1-2 lbs per week. 

Next, eating clean and balanced meals. 

While being able to eat whatever you want is certainly how some people hype up intermittent fasting, that’s not how you should go about it if you want to maximize its effectiveness over the long haul

Rather, choose whole foods that get you your fair share of nutrients. These include fruits and vegetables, lean sources of protein, healthy fat, and the right amount of carbohydrates.

Take a look at our list of foods to eat when trying to lose weight and fit them into your feeding schedule. 

Another way you can maximize intermittent fasting is by pairing it with other weight loss techniques, like keto and weight lifting. 

This leads us to the next part.

Can you do intermittent fasting with keto?

Absolutely. As a matter of fact, the whole theory behind how intermittent fasting amplifies fat burning is that the prolonged fasting hours forces your body into a temporary state of ketosis where you use your own fat for energy.

Having said that, if you have plans on doing the ketogenic diet, you could ease yourself into ketosis with intermittent fasting. 

Then, when you’re in ketosis, you could either eat using a normal schedule or continue using IF methods while choosing keto-friendly foods. 

Can you do intermittent fasting while lifting weights?

Yes sir, you can. Not only that, this combination has been quite popular within the fitness community for some time now. However, there are a couple of tweaks you have to make:

  • One, you need to schedule your workouts around your diet, and
  • Two, you need to adjust your macronutrients

On scheduling your workouts…

Please, please, please don’t workout on days where you’re fasting. It’s simply counterproductive. 

Your body needs carbs, fat, and protein to grow and/or repair your muscles. So, when you’re eating less than 600 calories, there’s just no way you can give your body the raw materials it needs. 

Instead, schedule your training on days where you can feed before and after your workouts. 

To paint you a better picture, let’s take the 5:2 and eat-stop-eat sample schedule I showed you earlier and add a workout split:

Day of the week Fast or Eat Workout or Rest 
Monday Fast Rest
Tuesday Eat Workout
Wednesday Eat Workout
Thursday Eat Workout
Friday Fast Rest
Saturday Eat Workout
Sunday Eat Workout

Of course, this concept applies to other methods. Adjust the workout split accordingly. 

On adjusting your macronutrients…

When you lift weights and fast at the same time, I’m assuming it’s because you want to lose weight while keeping as much muscle as possible. That is, after all, the combined purposes of these 2. 

Having said that, research says that a bodybuilder’s total calories should compose of:

  • Carbs: 50-60%
  • Protein: 25-30%
  • Fat: 15-20%

Though you probably aren’t a bodybuilder, I believe you should still use these numbers as a rough guide whenever you’re in your feeding window. 

The higher protein intake will give your muscles the amino acids it needs to repair itself, the carbs help make sure you have energy to fuel your workouts, and the fat is there to help manage your hormones. 

Conclusion

In my opinion, Intermittent fasting and all its various methods are truly fascinating. You can use IF alone and lose weight through sheer calorie reduction, or you can combine it with exercise and other weight loss methods to amplify its already tremendous potential. 

The key here, however, is to make sure you choose the right type that works for you, don’t overeat during your feeding hours, and choose healthy food whenever you do eat. 

And with that, I take my leave. Do me a favor and share this with your friends, will ‘ya? Awesome! 

Article by:

Kristopher Ceniza

Kristopher Ceniza

I’m Kristopher, a writer for Sprout Origin. I’ve been writing professionally for quite a few years now but even before I pursued it as a career, writing has always been my safe haven. I’m also an avid gym-rat with a penchant for aesthetics and functionality, an ardent basketball fan, and a car/motorcycle enthusiast.

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