Keto Cheat Day: Can You? Should You? Maybe Try This Instead

Can you have a cheat day on Keto? Should you? We weigh the pros and cons...

By Mark Hamblin

I get this question A LOT:

Can I (or should I) have a cheat day on the Ketogenic Diet?  What about a cheat meal?

Well, if you’ve read my KetoJam Manifesto, you already know my opinions on the subject.  But let’s weigh BOTH the pros and cons, without judgement for anyone on either side of this controversial issue…

My Personal Experience with Cheat Days

Personally, I’ve tried it both ways.  When I first started out, I tried doing a weekly cheat day, and I picked Saturday.

I figured it was a good mental trick — I could make a bargain with myself to stay “strict” during the week, and would only have to delay my indulgences by a few days until I made it to the weekend.  Quite a good deal, I thought!  And I figured that would be a good “hack” for making this sustainable for the long term.

I made it through the first few weeks following this plan.  I maintained strict Keto during the week, then “indulged” on the weekends, often with pizza, sushi (with rice) and ice cream.  Oh, that sugary ice cream.

I would notice (quite logically) that when I weighed myself the day after a cheat day, my weight would jump up.  And I would be quite thirsty.

Why?  Well, when you start a Ketogenic Diet, the first weight you lose is water weight… that’s normal.  When you eat a carb-heavy diet, your body retains a lot of water.  Then when you enter ketosis, your body starts releasing this retained water, and you often notice a quick drop in weight.  So when you go back to eating carbs, you start retaining water again.

After a few days of being back on strict Keto, my weight would drop again… usually around Tuesday.  But this big fluctuation was tough to deal with each week.

Besides that, I noticed some other things about my cheat days:

My cheat days were turning into cheat weekends, then cheat weeks, then cheat months.

With my cheat day on Saturday, it was really easy for Saturday to turn into Sunday.  It’s still the weekend after all!  Before long, all my cheat days were AT LEAST a full cheat weekend, and I would be lucky if I would recover by Monday.

Trust me… I really did want to get back on strict Keto, but the thought going through my mind was “well… just one more cheat meal… I mean, I just had some carbs 4 hours ago, so what’s the harm in just having a little more.”  I call this the “DSM Thinking” — Diet Starts Monday.  As much as the wise part of my brain wanted to stick to my plan, the impulsive side of my brain would win.

After about a month and a half, one of my cheat weekends turned into a full fledged cheat 3 months… I went back to my old ways, and it was just so darn hard to get started again.

Once I did finally start Keto again, I swore off cheat days, and I have no regrets about it.

Does that mean I’ve never cheated?  No, certainly not.  But I just don’t plan them on a regular occurrence.

Why Cheat Days Don’t Work

I already spelled out my experience with cheat days, but perhaps I am just a weak person.  Perhaps you have stronger willpower than I do.

Certainly a good chance of that!

But I think there are some very specific scientific psychological reasons why cheat days are bad for “diets” and any other self-improvement plan, and particularly bad for the Ketogenic Diet.

1. You’ll never become fat adapted.

Just because your body is producing ketones does not mean that your metabolism is truly “fat adapted.”

Your body (liver) will start producing ketones from fat once it realizes there is not enough glucose for energy.  But that doesn’t mean your body can efficiently run in this state yet.  There are many different metabolic sub-systems that need to adjust, and that process can take weeks, sometimes even months.

Once this DOES happen, your body can start to efficiently use stored fat as energy, and you’ll feel more comfortable in ketosis.

But if you’re frequently cheating, you will never allow this to happen.

Sure, if your cheat days are spread far enough apart (months) then you may not have to worry about this one, so I’m mainly talking about weekly cheat days for this one.

2. The odds are against you.

I believe that for everyone, there is some likelihood that we won’t recover from a cheat day — we’ll fall off the Keto wagon and let the cheat keep going for an extended period, if not forever.

For some people that is maybe a 1% chance, and for others it is a 90% chance.

Let’s just say, for example, that you have a 25% chance of completely falling off the wagon every time you cheat.  A 25% chance that you won’t recover when you want to.

Pulling out our old statistics textbook (sorry, I’m a trained engineer), that means that after one month (4 weekly cheat days) you only have a 31% chance of sticking to your plan — way below 50/50 odds!

Even if you’re 90% certain you’ll get back on track after a cheat day, after only 7 weeks, your odds of still being on your plan are less than 50%!  (47.8% to be exact)

Of course, people are not calculators, but you get my point.

If you roll the dice with cheat days enough times… you’re bound to get burned at some point.

3. You’ll feel like crap — physically and emotionally.

In the 1-2 days after a cheat day, I would always feel like complete junk.

Physically, I would feel bloated and puffy, mainly from the extra water my body would be retaining.

And mentally, the big jump in scale weight would be a bit demoralizing.  I consider myself to be quite good at not getting too caught up in daily weight fluctuations, but a 3, 4, even 5 pound increase in weight on a weekly basis was just hard to deal with, even though I knew it would drop back down once I was strict again.

The constant yo-yo effect was just tough.

4. It’s hard to build good habits and it fuels your obsession.

Losing weight and changing the way you eat is all about habit change, whether we like it or not.

And the only way to build habits is to actually do something… consistently.

If you’re constantly going back and forth, you’re never going to build the habit of staying away from carbs.  And you’ll continue to fuel your obsession.

The carbs will always be on your mind, and you’ll always pay attention to them.  You’ll drool over them, get all worked up about how you’re going to destroy an entire pint of ice cream on your cheat day.  You end up just fanning the flames of your obsession.  Not a good place to be.

Once I stopped doing cheat days, the obsession started going away.

And now?  Honestly, I don’t even notice most of that stuff.  The sugary treats in my office break room?  They blend into the surroundings.  The candy for sale at the supermarket checkout?  Don’t even see it.

Its hard to believe, but its real.  Quit fueling the obsession and it goes away.

5. Cheats will happen anyways… save your energy for those.

Yes, I’ve been Keto for 5+ years now, but even for me, cheats still happen.  Sometimes they’re somewhat planned, like when I go to visit my in-laws.  Or sometimes they’re not planned, and my willpower isn’t strong enough to keep me away from something special.

I’m not an angel.

Cheats are bound to happen.  But they take real strength and willpower to get through and recover from.

Save your mental energy and willpower for when you actually need it — not because you want to have pizza every weekend.

Can Cheat Days Ever Be a Good Thing?

Yes, I said we’d review the pros and cons… right.

Are cheat days ever a good thing?  Or maybe for certain people?


I can certainly appreciate the need for “mental strategies” that we can implement to help us build healthier habits and make change more sustainable.  After all, that’s what I thought I was doing with using a cheat day to begin with.

I think cheat days may have some benefit under the following conditions:

  • If you’re honest with yourself about the risk of a cheat day turning into something longer, and if you have a high chance of being disciplined about it (that’s not me)
  • If you know in advance that the scale WILL move in the “wrong” direction, quite significantly, when you cheat
  • After you’ve already become fat-adapted (give it at least 2 months)
  • If you’ve never cheated before, and you want to see what effect it will have on your body (perhaps you want to “learn your lesson” about cheating… never to do it again)

Otherwise, I do strongly you suggest you stay away from cheat days.

What To Do Instead

Like I said… I really am a fan of implementing certain “mental hacks” that we can use to keep ourselves on track and moving towards our goal.  After all, I think the mental side of Keto is really the hard part… learning the “what” is the easy part…. learning the “how and why” is harder.

But I just don’t think cheat days are one of those good mental hacks.

So what do I do instead?

I alternate between strict Keto and something more like “lazy keto”, going 1-2 weeks strict, then 1-2 weeks less strict.

When I’m strict, I’m strict.  No artificial sweeteners, no “fake breads”, I really limit my total carbs, and I exercise nearly every day.  I usually lose weight quite quickly in this “mode.”

Then when I’m “taking a week off” I’m still eating low-carb, but I’m less strict.  I’ll have a bit more “Keto junk food” like Quest Bars and Keto desserts, I’ll pay less attention to my overall quantity of food, and I’ll eat more things from the yellow column of the KetoJam Keto Diet Food List.  To me, this feels like “cheating” but without the horrible consequences of eating lots of real sugar and carbs.  I don’t necessarily lose weight while in this “mode” but that’s OK — I could live like that forever, without much risk of wanting to cheat.

This approach is completely sustainable in my opinion, and one that I suggest for a lot of people trying to lose weight with the Ketogenic Diet.  It works for many of the same reasons that people think cheat days work (short-term delayed gratification) but without the huge downsides.

I’ll write a whole separate post about it… but until then, maybe give it a shot.

Keep it real, and keep it Keto.


Mark Hamblin

Mark is a Keto Diet blogger, author, and coach, helping people all over the world reach their individual weight-loss goals. He has been following the Ketogenic Diet himself since 2013, achieving a staggering transformation from a very unhealthy 405 pounds to 195 pounds today. As a day-job, he works as an executive in the global electronics industry. He splits his time between San Francisco, Copenhagen, and China.
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