We’ve all done it…

After working hard and eating healthily all week, suddenly your cravings get the better of you and you end up fisting a chocolate cake that’s large enough to feed a village.
C’est la vie.
But how damaging can these off-plan days be?
I mean, is it even possible to ruin a whole week of hard work with one single blow-out?
You’ll get mixed responses depending who you ask in the gym, so I dived deep into the scientific research on weight loss, cheat days, and diet sustainability, in order to find you some 100% definitive answers on the topic. Enjoy!

For Most Of You The Answer Is “No”
Your diet is a long-term thing, so these so-called “bad days” generally won’t ruin your results.
Heck, it’s actually pretty normal to have them.
You see, it happens because the process of getting fit and healthy is long and can be frustrating at times, so after a sustained period of effort we begin craving the stuff we used to eat.
And providing you continue working hard in the gym and just get back on track with your nutrition the following day, those so-called “bad days” will not ruin your progress at all. Sometimes they actually even help you, because they act as a little reprieve from the dieting process and they get you to think about your long-term goals.
Plus, the biological process of taking those excess calories and storing them as fat takes roughly 5-6 days (de novo lipogenesis), by which time you’ll already have burned it off in the gym without any negative impact on your results!

For Some Of You The Answer Is “Yes”
If this happens every few days, or every weekend, then we need to look at it.
It tells me that your diet is too low in calories, or is based around foods you absolutely hate.
I’ve met countless people who fall victim to this (heck, even MyFitnessPal have a 43% reduction in logins at the weekend!), and your diet is a numbers game so it’s the frequency of these so-called “bad days” which is sabotaging your results by throwing your weekly numbers out of sync.
For example, Jane believes she’s eating 1400 calories per day and not losing weight. Upon closer inspection we notice that she’s correct but she’s only tracking her food between Monday to Friday.
Jane tends to feel frustrated to fuck by the time the weekend arrives, which triggers a binge, and if we add in these untracked calories we notice that her weekly average is really 1700 kcals/day, not 1400 kcals/day.
Another issue that she faces here, though, is that even though she’s technically NOT in a calorie deficit over the course of the whole week, she still feels the tiredness and frustration associated with dieting because she’s working hard for 5/7 days.
This feeling of frustration is ultimately what causes most diets to break down.
3 Techniques To Stop These “Bad Days” Wrecking Your Progress
If you find yourself in a situation which looks similar to Jane, here are three techniques I’ve used with clients over the years.
The first one is my personal favourite.
- The “Clean Slate” Method
You know that I’m all about creating a healthy relationship with food and not worrying about every little fucking detail, right?
Well, enter the “clean slate” method.
Put simply, you’ll move on from your unplanned “bad day” and never worry about it again – ever!
I know that sound crazy (especially in a fitness landscape full of fitness douchebags who promote the idea of self-punishment and body shaming), but trust me, I’ve used this technique with more people than I can even remember during my 22 years as a PT and it always (AL-FUCKING-WAYS!) works.
You see, by moving on and just getting back on track the following day we learn over time to get past the stress and guilt which is associated with going “off track”. It’s often this stress and guilt which causes us to make things worse.
For example, how many times have you eaten one unplanned snack and then “pushed the fuck it button” because you thought you’d wrecked your whole diet? Exactly!
Without those negative emotional attachments, most people learn how to become more consistent and their diet is easier to sustain because they develop a healthier relationship with food by understanding that it ain’t such a big fucking deal. (1, 2)
- The “Small Chunks” Method
The first method was more of a long-term strategy, but in certain situations you’ll actually want to burn off those unplanned excess calories.
For example, this may apply to someone who has a deadline for a fitness goal (e.g. a bodybuilding show, a holiday, or a wedding).
Now, I’ve always preferred to “work off” excess calories by making changes to my diet rather than my exercise program, so that’s what we’ll do here. The “small chunks” method has you break down your excess calories and gradually erase the surplus next week by making small reductions each day until it is fully gone.
Let’s go back to our example with Jane, who believed she was eating 1400 calories per day but was actually eating 1700 when we factored in her weekend cheat days. So instead of eating her planned 9800 calories per week she really ate 11900 calories, so she was 2100 kcals over her weekly budget and that’s why she didn’t lose weight.
If she wanted to work this off she could use the “small chunks” method to do it.
One way you could do this is to be aggressive (e.g. reducing calories to a low level for the first three days of the following week, such as 700 kcals on Monday, Tuesday, and Wednesday, and then back to 1400 thereafter):
However, I’m not a fan of that approach.
I’ve always preferred a less aggressive approach (e.g. keeping calories at 1400 on Monday and Sunday, then reducing every other day to 980). In my experience this approach gets better results because the reduction is much more tolerable.
- The “Holy Fuck” Method
As mentioned above, I’ve always preferred making changes to my diet to work off a calorie surplus.
However, in certain situations you can also increase your workout intensity.
Because as the old saying goes, “If you create a big enough fire, you can throw anything on it.”
I call this the “holy fuck” method because it’s the hardest of the three, and generally one that I reserve for when all else has failed.
This is where you’ll make a slight reduction to your calories in the following week (or even just keep them at maintenance level) but also agree to burn through the surplus by increasing the amount of cardio you do.
Now, it takes around 1-minute to burn through 7 calories on a stationary bike, so if Jane kept her calories on Monday and Sunday at 1400 and reduced her every other day to 1250 she could then erase the remaining 1350 calories by doing 27-minutes of stationary bike work every day.
Alternatively, she could keep her weekly calories set to 1400 and try to blast their entire 2100 surplus by adding 42-minute of stationary bike work every day.
Can you see why I don’t really like this approach?
The first reason is because tracking your calorie burn is quite difficult so there’s a degree of guess work (or relying on the machine’s built-in calorie burn tracker) involved. The second reason is because with increased training comes increased injury risk. And the third reason is because it increases the length of time you’re in the gym; let’s not forget, this additional cardio is on top of your normal workouts.
Also, the more we increase our workload, the more our body is able to adapt. A recent study from researchers at the University of Ottawa showed that the body can actually reduce the rate at which we burn calories by as much as 28% when we subject it to an overly excessive workload on a regular basis, so while I acknowledge that the “holy fuck” method could useful from time to time, it’s not something I want you to use very often. (3)
Instead, I’d rather you focus on your nutrition.

Further Reading:
If you enjoyed this blog, then you’ll probably also like reading these.
>> Why I Ditched “Clean Eating”
>> What Is “Last Supper Syndrome”?
>> Is Food Eaten Late At Night Stored As Fat?
References:
- Hall K. D., et al. Maintenance of lost weight and long-term management of obesity. Med Clin North Am (2018)
- Stewart T. M., et al. Rigid vs. flexible dieting: association with eating disorder symptoms in nonobese women. Appetite (2002).
- Halsey L. G., et al. Energy compensation and adiposity in humans. Curr Biol (2021).
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