Why Do I Lose Weight After Cheat Day?

You asked “Why do I lose weight after cheat day?” so we found out for you. Turns out, if you are finding yourself dropping a handful (or a big bunch!) of grams after directly your cheat day, you may be experiencing metabolism fluctuations.

What (and Why) is a Cheat Day?

A cheat day is one day out of several (usually a week) when you deliberately exceed your daily calories target. For example, if you are following a 1500 calorie diet, your cheat day might allow you to eat 2500 calories instead of the usual 1500. In fact, you might not even have a limit at all, instead eating whatever you want, all day long. The main reason for a cheat day is to supply your body with whatever it might be craving, so that you can begin the next “normal” diet day with more motivation and less of a sense of deprivation.

Cheat Day means Eat Anything

Cheat Days sometimes cause Extra Weight Loss

The surprising thing is that, sometimes the cheat day results in significantly more weight loss than usual for about 48 hours after the “cheating” period. How could this be? Doesn’t the calories in/calories out equation mean that you should always gain weight when you eat more than you use in a given timeframe? Not necessarily, at least in the short-term. Over the course of a fortnight or a month, a calorie deficit or surplus will surely do its inexorable thing, but in the short term weight changes are far more susceptible to rapid metabolic changes caused by hormones like leptin.

Weight Loss after Cheat Day

Cheat Days affect Hormonal Balance

After you have been on a calorie controlled diet for a while, your body starts to adjust itself to the lower input energy lifestyle. Your hormonal balance changes as your body tries to maximise the effect of all the food you eat. It tries to slow your metabolism so that it uses only what fat stores it has to (the body hates to break itself down). Now, into this internal environment, comes the cheat day. Suddenly, there are way more calories coming in than “usual”. Your body quickly tries to adjust again, this time by increasing the metabolism!

Leptin changes after cheat day

Cheat Day Aftermath

So now, the day after Cheat Day, your body has released hormones which speed things up, because it expects another surplus calorie day. Instead, it is a calorie deficit day! It takes a couple of days to get back to the slower metabolism day, so in the mean-time you burn fat faster than you did before the cheat day. The result is weight loss, providing that the fat loss exceeds the fat gain from the cheat day calorie surplus. That’s why you notice weight loss after cheat day, rather than the expected weight gain!

How Much Weight do you Gain on Cheat Day?

Assuming that you do not experience hormone-triggered weight loss, how much weight can you expect to gain on (or just after) cheat day? Let’s say that on cheat day, you eat 160% of the calories you usually eat. According to “overfeeding” studies, an average person can expect to gain about 200 grams of fat for a day of eating a 60% calorie surplus.

Of course, your individual result could be very different, depending on a huge number of variables!



Don’t Count on It!

Yes, weight loss after cheat day is a real phenomenon that has been studied by real scientists, but don’t count on it! Everyone’s metabolism is different and peoples’ bodies react differently to cheat days. You might lose weight faster than usual after a cheat day, but you might also just undo a week’s worth of hard-won weight loss. The only sure-fire way to succeed with weight loss is to maintain a calorie deficit for long enough. If you have cheat days within an overall calorie deficient period, no problem. Just don’t let one cheat day become two, three, four consecutive cheat days!

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