Recently I wrote an article about why fasting is the best way to reduce body fat (and a lot more effective than counting calories).
Today’s article will make a lot more sense if you read that one first. So if you haven’t yet, go do that now! 🙂
This time around, I’ll share with you a practical framework about how you can use fasting to lose weight.
I created this framework through a combination of my own experience, and tons of research (books, podcasts, articles, individual success stories, and so on) over several years.
I can’t guarantee you’ll have a smooth journey–it’s natural to have some setbacks when you try something new.
But if you use this approach and stick with it, I’m confident you’ll be able to lose body fat, break through plateaus, and ultimately reach your goal weight.
Your Weight Loss Timeline
Sometimes patients come to the emergency room (where I work) with a problem that’s been going on for years, and they’ve visited multiple specialists… and then they expect us to fix it overnight.
Obviously, that’s not realistic.
Similarly, if it took years for you to gain all your excess weight, don’t expect it to go away in one day (or one week, or one month).
How fast you lose weight will depend on your health status (e.g. insulin resistance makes it slower) and other variables.
Men tend to lose weight a little faster at the beginning, but women usually catch up after several weeks if they don’t give up.
Whatever your individual situation is, be patient. There’s no rush.
When it comes to making lifestyle changes, you’ll have an easier time sustaining your progress if you take things slow and give your body (and mind) some time to adapt to a new way of living.
Other Key Reminders
In terms of mindset, here are a few CRITICAL things to remember. I’ll mention some of these points later as well, even multiple times, because they’re worth repeating.
1) Make sure you eat enough in between fasts! FEAST when you’re not fasting. Instead of counting calories, eat until you’re full and satisfied at each meal.
2) Don’t feel guilty about eating. Eat slowly, and enjoy your food.
3) Don’t obsess over the number on the scale. Short-term fluctuations are often due to fluid shifts, hormonal changes, etc. There will be ups and downs. If you find you’re obsessed over the numbers, put the scale away and don’t weigh yourself every day.
4) Don’t make losing weight your only goal. Notice progress in other areas as well (like how you feel, how your clothes fit, improvements in blood sugar, mobility, and so on). These “non-scale victories” are equally if not more important.
Now let’s get into the weight-loss framework.
Phase 1A: Time-Restricted Eating (TRE) Gives You a Solid Start
Time-restricted eating (A.K.A. “intermittent fasting”) means eating all your food in a shorter window of time each day, like 11 a.m. to 7 p.m. (8 hours).
That could basically just mean skipping breakfast, or skipping dinner (whichever is more convenient or easier for you).
If you’re new to fasting, start with TRE.
It gives your body more time to burn body fat each day, and you may also eat a little less since you’re skipping a meal.
Keep in mind, you don’t have to shorten your eating window from one day to the next. You can do it gradually, and let your body slowly adapt.
Here’s one simple approach:
Skip breakfast (or dinner) one or two days a week at first. Then gradually increase to 3 days, 4 days, and so on.
Ideally, avoid snacking (because it raises your insulin more frequently), and focus on full and satisfying meals instead.
Make sure you eat plenty of healthy fats, as well as a decent amount of protein. This will keep you satisfied for a long time, and make it easier to fast afterwards.
How to Use TRE for Weight Loss
In phase 1, use TRE (on most days) for at least 2 months. Then reassess.
If you only do it for a week or two, that’s not long enough to really judge your progress. Your body needs some time to adapt to eating less frequently, so don’t be in a huge rush.
If you have to ease into it slowly, that’s probably smart. But keep going for at least a couple months after that.
Some people actually reach their weight loss goals just by doing TRE. So if it’s working, keep going.
Other people kind of plateau after a while, and need to change things up.
Either way, TRE is great for your health, and a solid way to start your weight loss journey.
Phase 1B: A Low-Carb, Ketogenic Diet Makes Fasting (& Weight Loss) Easier
You don’t have to do keto to lose weight. So this step is “optional”, but it gives you a lot of advantages.
A ketogenic diet means eating low carb / high fat (LCHF) until your body starts making ketones.
In other words, when you eat a ketogenic diet your body starts using fat as its main energy source. So you’re in “fat-burning mode” all the time.
Ketones also boost your metabolism, suppress your appetite, and help control cravings.
Sounds pretty helpful, eh?
How to Use Keto for Weight Loss
Try doing a ketogenic diet for at least 2 months in conjunction with TRE.
2 months is enough time that your body can kind of adapt to using fat for energy, instead of just carbs. In other words, you’ll be “fat-adapted”, which makes your metabolism more flexible.
Once you’re fat-adapted, fasting gets easier.
It also helps if you do a ketogenic diet for a week or so right before any longer fasts you do in the future.
Your brain needs ketones when you fast for more than a day or so. So getting your ketones up in advance naturally makes the transition into fasting a lot smoother.
How Do You Know if You’re Eating a Ketogenic Diet?
By definition, you’re eating a ketogenic diet if and only if your ketones go up.
So measure your ketones.
Urine test strips, breath meters, and finger stick devices are all available. Any of those are okay, but if you’re a beginner you may as well just get some cheap urine strips.
They’re not perfect, but they’ll at least give you a “yes / no” answer about whether you’re in ketosis. (FYI, “ketosis” means you have ketones in your blood.)
You should also count your carbs, at least to start.
You can work your way down gradually, but after a while try to keep your carbs under about 30 grams per day. And keep measuring your ketones to see how you respond to different foods.
Just like with fasting, it’s a good idea to ease into keto as well.
For example, you could slowly reduce your carb intake over a few weeks, so you don’t go through major “carb withdrawals”.
(By the way, my Easy Fasting Guide tells you exactly how to do this.)
What Can You Eat on a Ketogenic Diet?
There are myriad options, but the key is to keep your carbs low and your fat intake high.
Here’s a basic idea:
Include things like meat, fish, poultry, eggs, leafy greens, other non-starchy vegetables, berries, nuts, cheeses, avocados, coconut oil, olive oil, and butter.
That’s not a complete list obviously, but that should give you quite a few options to consider.
I’ve also created a really thorough list of simple and easy ketogenic food options, so if you’re thinking about trying low-carb check that out as well!
By the way, you’ll probably need to increase your salt intake on keto as well, because once your insulin level drops you’ll be peeing out more salt than before.
Don’t Be Afraid of Dietary Fat!
Women in particular tend to be scared of eating high-fat foods, because they think it’ll make them fat.
That’s a myth.
Eating fat doesn’t make you fat.
In general, it does quite the opposite. Eating fat helps control your cravings, so you’re less likely to eat the truly fattening foods (sugar & other processed carbs).
Healthy fat sources include things like avocados, nuts, coconut oil, olive oil, sardines, other oily fish, free-range eggs & poultry, grass fed beef, and even butter.
(Unhealthy fat sources include most processed foods, vegetable oils like soybean/canola/corn oil, bakery products, and anything deep-fried at a restaurant.)
The sooner you stop being scared of dietary fat, the better off you’ll be.
Embrace the fat! 🙂
Phase 2: Medium-length Fasts Help You Conquer Plateaus
By now you’ve done TRE for at least a couple months. And maybe keto at the same time, for all the added benefits.
After that, if your weight loss stalls it’s time to move on to phase 2.
Doing slightly longer fasts in the 24 to 36 hour range can help you break through weight loss plateaus.
They give you a little extra time to transition into-fat burning mode, which accelerates your progress.
They also give you another advantage:
Longer fasts can help reduce fatty deposits in your liver and pancreas, which improves your body’s sensitivity to insulin. That makes it easier to lose weight!
24 Hour Fasts
On TRE, you were basically skipping one meal a day (breakfast or dinner). To do a 24 hour fast, you’d skip two meals in a row.
For example, if you eat lunch on Thursday, don’t eat again until lunch on Friday. That’s about 24 hours, and you skipped 2 meals.
36 Hour Fasts
The nice thing about a 36-hour fast is that it means you can skip a whole day of eating. That gives your body quite a bit longer to burn fat, without significantly disrupting your meal timing on the other days.
For example, you could have dinner at the usual time on Monday, then fast all day Tuesday, and eat breakfast on Wednesday.
Your Fasting Schedule: How to Use 24-36 Hour Fasts for Weight Loss
You can experiment and work your way up gradually, but here’s a protocol that’s worked for lots of people:
Fast for 24 or 36 hours 2-3 times per week.
Keep that up for at least a couple months, and then see how you’re doing.
If you’d like, you can keep doing time-restricted eating on some of the other days as well. But don’t overdo it.
Make sure you FEAST in between fasts. Eat until you’re full, and satisfied, including plenty of protein and healthy fats.
One way to know if you ate enough?
You’ll have a “food baby”. 😉 That’s a positive sign.
As I mentioned earlier, becoming “fat-adapted” makes fasting easier. So consider doing keto for a while beforehand.
Once you start doing longer fasts, it’s really important to keep your electrolytes up as well. Mainly that means getting plenty of salt / sodium, which you can do by drinking bouillon, broth, or other salty things while you fast.
Magnesium and potassium supplements may also be beneficial.
For some other tips to make your experience as easy as possible, read my Easy Fasting Guide.
Phase 3: Prolonged Fasting (> 36 hours) Gives You an Optional Boost
This phase is mostly optional, and you can probably reach your weight loss goals with a combination of TRE, low-carb, and medium-length fasts.
On the other hand, extended fasting is the quickest way to burn body fat, and it may help you break through some more stubborn plateaus.
As a bonus, longer fasts take you through additional “stages” of fasting and give you a BUNCH of other health benefits besides weight loss.
How to Use Extended Fasting for Weight Loss
Once you’ve tried TRE, a ketogenic diet, and some medium-length fasts, if you’re still trying to lose more weight consider this-
Option 1: Do a 3 day fast (~72-84 hours) every other week.
Option 2: Alternatively, do a 5-7 day fast about once a month.
You can sprinkle in some 24 or 36 hour fasts as well. But don’t do them right before or right after these longer fasts.
Instead, take some time to “refeed”.
For example, if you fast for 5 days, eat for at least the next 5 days before you start fasting again. This gives your body a chance to refuel and rebuild after your fast.
As always, eat plenty of high-quality food when you’re not fasting!
Prepare Yourself For Success
Prolonged fasts are not a trivial matter, especially if you’ve never tried it before. So use the tips in my Easy Fasting Guide, and make sure you keep your electrolytes up.
As I mentioned earlier, the transition into fasting is significantly easier if you do a ketogenic diet for several days beforehand.
I’ve done long fasts with and without this step, and it’s definitely worth it. Especially if you’re a beginner.
Don’t Go Completely Crazy
By the way, you’ll hear about people doing even longer fasts (10 days, 20 days, or even more), but for the purposes of weight loss you really don’t need to do super-long fasts.
More is not always better–and there are some increased risks the longer you go (like refeeding syndrome). So no need to go hog wild.
Phase 4: Maintain Your Progress
Say you’ve used a combination of the strategies above and reached your weight-loss goal. Now what?
Here’s the basic idea:
Do enough fasting to balance things out so that you maintain your ideal weight.
In other words, you may not need to do as much fasting as you did to lose all the weight. But you’ll probably need to do some fasting to make up for the feasting you’ll do on special occasions (especially if that involves junk food).
So keep an eye on things, and find a pattern that works for you to maintain a healthy weight.
This could mean using TRE on a regular basis, or doing longer fasts less often. Or a combination of both.
Putting It All Together
I’ve mentioned some of these points before, maybe even multiple times. But that’s because they’re all important enough to repeat 2 or 3 (or maybe 17) times. 😉
Start Slow, Like a Workout Regimen
Fasting is kind of like working out. You need to build up your stamina, and it may be hard at first.
If you’re like most people, you haven’t done much fasting before. There’s no need to rush into it.
Pretend you’d never exercised in your life. How would you start? Probably not by running a marathon the first day.
Similarly, you don’t need to rush into fasting. Start slow, and gradually build up your fasting capacity.
Tools in Your Toolbox
Work through these phases in order, and take it slow.
But once you learn the ropes, think of TRE, ketogenic diets, medium-length fasts, and prolonged fasting as tools in your toolbox.
You can mix and match, and experiment. Keep trying different things, and see what pattern or combination works for you and your lifestyle.
Fasting Versus Feasting
I’ve said it before, and I’ll say it again (and again…and again):
When you’re not fasting, you need to FEAST.
If you try to fast AND cut calories, you probably won’t be eating enough food overall, and your metabolism could slow down (just like it would if you did a diet where you cut calories every day).
Many of us have been “professional dieters” for years, and we have a hard time eating without feeling guilty. This is especially true for women.
It may take some time to shift your mindset, but keep working at it. Stop counting calories, focus instead on the TYPE of food you eat, and eat until you’re full and satisfied at each meal.
By eating enough food in between fasts, you’ll keep your metabolism strong, and be able to keep losing weight in the long run.
Exercise Makes You Healthier…and Heavier?
Exercise isn’t that effective for weight loss specifically, because you can never do enough exercise to make up for a terrible diet.
But it’s super good for your physical and mental health! So I hope you’ll incorporate plenty of movement into your lifestyle.
Keep in mind though, exercise builds strength, and increases muscle mass.
If you gain even a little muscle, that will technically slow down your weight loss. In other words, if you’re losing fat and gaining muscle at the same time, you could be getting healthier without your weight changing at all.
That’s one more reason to look for “non-scale” victories, rather than obsessing over your weight.
Keep Changing Things Up
When you plateau, that usually means it’s time to try something different.
Don’t be afraid to change things up. Keep your body guessing.
In the framework I’ve presented here, that usually means trying a slightly longer fast, reducing your carb intake, or a combination of both.
It probably took years to gain the weight, and it may take a while to get it all off. Don’t give up just because you haven’t lost all your excess body fat in a week (or a month, or 6 months).
It’s not about doing a crash diet. It’s about a sustainable and healthy lifestyle.
Time-restricted eating (A.K.A. intermittent fasting) is an effective tool for reducing body fat, and some people reach their weight loss goals with TRE alone.
But if you try that for a few months and your weight loss plateaus, it’s time to move on to some longer fasts.
Eating a ketogenic diet can accelerate your fat loss, and also makes fasting easier.
If you have a lot of weight to lose, you’ll probably need to change things up periodically, and keep your body guessing.
Be patient – if it took years to put your weight on, don’t expect it all to come off overnight.
Think of fasting like a new lifestyle, and not some sort of crash diet.
Take it slow at the beginning, and let your body adapt gradually. Easing into it makes things more sustainable in the long run.
In between fasts, it’s important to eat enough food. In other words, feast when you’re not fasting. This includes eating plenty of healthy fats, and adequate protein.
If you use the framework I’ve presented in this article, and stick with it, I think there’s a good chance you’ll reach your weight loss goals.
So write down your plan, identify the first small step, and get started today!