A: I love your enthusiasm, Nancy! I get this question a lot from folks who either want an excuse to “cheat,” or like you, want to make sure they’re doing everything they can to ensure their success.

First, what exactly IS a “cheat day”? A cheat day is a strategically planned day included in a meal plan (usually a weight loss plan), where it is permitted—and actually encouraged—to cheat on your diet. Some people might also call this a “free day” or a “diet break.” Although it’s a matter of semantics, choosing the right terminology can be a useful reframing tool.

Simply put, a cheat day is not necessary. In fact, both scientific research and real-world experience show that you can get great fat loss results with daily caloric restriction. Having said that, there may be a couple reasons why a cheat day may be beneficial.

For starters, many suggest that a strategically planned cheat day has metabolic benefits, which ultimately results in enhanced fat loss. More specifically, a cheat day is thought to boost levels of key fat-burning hormones, particularly leptin.

Let’s take a step back for a moment to see why this may be important.

The Health Benefits of a Cheat Day

You see, leptin, a hormone produced by fat cells, is often referred to as a “satiety hormone” because it is responsible for regulating food intake and energy expenditure. In other words, it governs how much you eat and how many calories you burn. For instance, when leptin levels are high, it suppresses hunger by telling our brains when we’ve eaten enough; on the other hand, when leptin levels are low, it urges us to seek food by increasing hunger.

Leptin is also referred to as an “energy-sensing” and “anti-starvation” hormone. Along these lines, leptin levels drop substantially with decreasing caloric intake. In fact, studies show that leptin levels can drop by as much as 50% just one week into a reduced-calorie diet. What’s more, because fat cells are responsible for secreting leptin, when you lose fat, leptin levels also drop, as you have less of the very tissue that produces this hormone.

The ensuing decline in leptin leads to a cascade of metabolic adjustments to preserve energy, including decreased metabolic rate (including reduced thyroid hormone production), reduced energy expenditure, and increased appetite. In other words, when leptin levels drop, you burn fewer calories, you move less, and you get hungry—really hungry. This explains, at least in part, why it can be difficult to continue losing weight over time (i.e., weight-loss plateau) and/or maintain weight loss.

Enter the cheat day.

You see, one way to temporarily boost leptin levels is to overeat, and overeating carbohydrates seems to have the greatest effect on leptin levels. In the short-term, this increase in leptin may counteract some of those metabolic adaptations and energy preservation mechanisms I mentioned above.

For example, some people respond to overeating by subconsciously increasing how many calories they burn. In other words, they move, fidget, and do more stuff without even thinking about it. In case you’re interested, the scientific terminology for this is non-exercise activity thermogenesis, or NEAT for short.

On the other hand, overeating can have an effect on subsequent eating behaviors. That is, many people tend to compensate for the overeating by reducing food intake in the following days. In other words, it basically makes it “easier” to get back to a reduced-calorie diet. This is at least in part due to the boost in leptin, and it may also come back to other hunger hormones, such as ghrelin, as well.

And that may be one of the biggest reasons why a cheat day “works”: It makes it easier to stick to your diet.

That leads me into another slew of reasons why a cheat day, or a brief diet break, can be a useful tool. Basically, it provides you with an incentive to stick with your diet plan. In other words, many people like your husband are more likely to stick with a diet knowing there’s a “break” in the near future. And at the end of the day, when it comes to weight loss, compliance is king. That is, the “best” diet is the one you can stick to.

That said, a cheat day is NOT a license to eat yourself sick. Rather, it’s simply an opportunity to eat some foods you enjoy—preferably with people who you enjoy—in a moderate manner. It doesn’t even have to be a full-blown, knock-down, drag-out, all-you-can-eat cheat day; in fact, in my experience, that’s counterproductive for several reasons. Some people find that having a single cheat meal or a special treat they’ve been craving is enough to jump-start their progress.

Overall, don’t feel restricted on a cheat day. Enjoy foods you might not otherwise on your “normal” eating days and do so in moderation. In the grand scheme of things, focus on consistently practicing good nutrition at least 80% of the time, and a few cheat bites here and there, a cheat meal, or a free day every now and then won’t hurt; in fact, it can be a very helpful tool.

Remember, an effective, personalized nutrition plan should help you establish good eating habits that you can continue to build on and integrate for the long haul. In other words, a cheat day (or break) is just an outlier as opposed to the norm.

Lastly, it’s really important to mention that cheat days aren’t for everyone. For some people, cheat days can lead to a downward spiral, completely derailing them from their diets. In the aftermath of a cheat day, some folks can feel downright awful—physically, mentally, and/or emotionally. So, if you fall into any of those categories, Nancy, then a cheat day may not be right for you. Just because everyone is doing something doesn’t make it right. It is your job to be your own diet detective to determine the best plan for reaching your goals.

Thanks for your question, and let us know if we can help with anything else.

–Coach Cristina