Should You Fast After Binge Eating?

Is fasting after binge eating worse thant eating normally ?

I love food and I often eat more than my share on weekends. I’m not bulimic and I don’t have an eating disorder, but sometimes my first reaction to eating a lot one day will be to fast for 24 hours. But isn’t fasting after eating a lot worse than eating normally?

If you practice intermittent fasting, after binge eating you should simply return to this diet to avoid shocking the body. Don’t get used to this binge eating/fasting cycle, and don’t start fasting for a few days afterward either, and you will be fine. A prolonged fast needs to be prepared and not rushed on the body as a punishment.

But how exactly would your body react when fasting after a binge? Why wouldn’t it be safe and healthy to compensate too much eating by a fast?

What happens to your body when you eat too much

Let’s first examine what happens to your body when binge eating.

I’ll not go into the emotional aspect of binge eating, including the addictive aspect of certain types of food (sugar in particular) and the fact that it can become an eating disorder. That plays a role in the way you feel when binge eating (dopamine rush at first, depression afterward), but not so much on how your body reacts to it.

Furthermore, there are a lot of consequences to frequent binge eating (insulin resistance, obesity, high blood pressure, diabetes), in short when it becomes an eating disorder. I’m not covering this, I’m only talking about binge eating as a once in a while thing.

One of the many pictures of food, lots of food, in my phone
One of the many pictures of food, lots of food, on my phone

So when eating too much, your organs will work hard to break down all the food you had, secreting extra hormones and enzymes. The stomach will secrete hydrochloric acid. In that case, more than usual.

That can cause what’s called acid reflux, when the acid backs up in the esophagus, also resulting in heartburn.

Your stomach and digestive organ will have a hard time dealing with all the food. It’ll swell, causing bloat, nausea and various discomforts. The stomach will also expand to adjust to the food quantity, pushing against the other organs and making you uncomfortable.

Your pancreas will release a larger than normal amount of insulin, producing a spike in blood sugar, which can then lead to overheating, headache, thirst, and fatigue.

The insulin released can be in excess and stay in your body. Which can have the strange result of making you hungry again later? Let’s say you had a huge dinner, then you might be hungry waking up.

The leftover insulin will trigger the hunger hormone, called ghrelin, as a way to make you eat… to get rid of the insulin in your body!

What about fasting after binge eating

First off, it might be hard to fast after a binge since the leftover insulin might make you hungry again. Furthermore, indulging in sugar or high carb could create cravings that might be hard to cope with the next day.

It might be best for you, even if you’re used to intermittent fasting, to have a normal eating day (a healthy one of course) if fasting is too hard on you.

Depending on how much food you had the previous day, fasting can be difficult
Depending on how much food you had the previous day, fasting can be difficult

But if you fast, let’s say, for 24 hours, which I have done plenty of time after weekends (but not always on those binge eating weekends, since that sometimes felt wrong), basically your body will act the same as usual.

It’ll lower your insulin levels and, after around 8 hours of fasting, the liver will have used the last reserves of glucose for energy (might take more time after binge eating). Your body will then enter into gluconeogenesis. Which means it’ll access your fat store and start breaking down your fat for energy.

You enter ketosis after around 12 hours of fasting. Some of the fat will then be transformed into ketone bodies, an alternative source of energy for the brain. A better source of energy.

After 18 hours, you’re fully into fat-burning mode and ketones become your main source of energy. Within 24 hours your body begins autophagy, which means it is recycling old components and breaking down misfolded proteins.

Okay, now that I’ve stated the obvious, what’s the difference between a normal day fasting and one after binge eating? I would say first it depends on your eating habits. If your body is not used to fasting, that’ll be hard, hell, it’ll be hard even without eating too much the previous day.

And it even might be hard if you’re used to fasting. As I said you’re pushing your body into extremes which might certainly not leave you feeling well. You might have cravings and a harder than normal keto flu.

But most of that is psychological and physiological, it will most certainly not cause damage to your body to switch back to fasting, even though the shock will make it difficult.

After putting your body through digestive problems, high blood sugar, high insulin, bowels discomforts, and acid reflux, you’re giving it time to restore himself.

The digestive system will be able to rest, lessening your body’s general energy expenditure and, if you experienced fasting, you know it can relieve a lot of stress on the bowels.

The real danger here is to make this a habit. To constantly indulge in food, then going back to fasting. This binge-eating / fasting cycle is a clear eating disorder and what is first a way to cope with a shock to the body, could turn into bulimia.

The other thing to take into account is a prolonged fast after binge eating. I’ve done this once and it was by far the hardest 4 days (yep, I stopped after 4 days when initially I was going for 7) fast I’ve ever done. And it was stupid too.

I felt the cravings, I spent 4 days hungry, feeling tired and on the last day, I had to take a vegetable broth in the morning (actually two). I was craving the salt (I only do strict water fasts, should I add) and feeling tired to the point of collapsing.

A prolonged fast should always be prepared. If you’re already intermittent fasting, you could slow down on the carb, food quantity and food density 2-3 days before the fast. That’s best practice, but shocking your body and metabolism is usually not the way to go.

What should you do after binge eating

It’s pretty easy: go back to your normal diet. If you’re an intermittent faster, go ahead. Do not add an additional shock to the body by changing your eating habits.

You should also drink a lot of plain water, keeping hydrated can help bring back balance to your body. Go back to your exercise routine, but do not overdo it, this could be dangerous as your body is still in repair mode.

Most of all, don’t feel guilty. Don’t punish yourself in any way, don’t add insult to injury by stressing about it. That’ll only leave you feeling bad and depressed which could lead to binge eating again.

Can binge eating help with weight loss?

Okay, I’m not advocating binge eating, but let me talk a bit about what we call cheat days. If you ever did a diet in your life, you know about them.

A cheat day is taking a break from your regular diet, one day of the week to eat anything you like. I do around 16-18h intermittent fasting 7 days a week, but on the weekend, I do not beat myself up with what I eat.

All cheat days are not created equals !
All cheat days are not created equals!

I’m not checking carbs, sugar or alcohol consumptions. I don’t do that every weekend, but most. Can that help you lose weight?

Well, as the great doctor Jason Fung, author of the obesity code, puts it: the effect of a cheat day may vary from person to person and it depends on your goals.

This means everyone’s metabolism is different and, even though you can train your metabolism through fasting, a cheat day can have a different effect depending on the person.

You should try it for two reasons :

  • Doing a cheat day a week for 2-3 weeks will not get you fat again in the blink of an eye. It might help you get out of a plateau or it might mess up your diet, but trying it won’t kill you.
  • If this is what you need to keep doing the diet, do it. Just keep your goals in mind, again, if it’s messing up your whole diet, restrict them.

Trying it might help you see if it’s the right fit or simply help you get through your actual diet. That’s the whole point of this blog: how to mix good eating habits with bad ones, without stressing your body in a bad way and with results.

Related questions

What should you eat after a binge? Anything that’s easy on your digestive system. Yogurt, kimchi, good bacteria to help your gut get through it. Also fiber (oatmeal, cereals), green tea to lower blood pressure, light vegetables (spinach, salad), ginger to relax muscles in your digestive tract. The usual good stuff!

Should you weigh yourself after a binge? Of course not. Beating yourself up with your weight immediately afterward will not help you get through it. You’ll weigh food you haven’t totally digested yet, water from excess salt, sugar, and alcohol, etc. Wait 1-2 days until you feel good again and you’re back on track to weight yourself.

Will a binge eating/cheat day ruin your diet? As I said before it will most certainly not ruin it. It could help mentally and even physically, but it won’t suddenly render your diet moot. Just go back to it, don’t think too much of your cheating day and go on with your life. Don’t be a drama queen about it!

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