We have been constantly plagued with different diets to achieve weight loss: intermittent fasting, keto, juice cleanses, paleo, Weight Watchers and of course, the most common, CICO. While there are many benefits and evidence for such a diet, there are also some serious catches. But first, let’s breakdown how this specific dietary plan work

The CICO diet is an abbreviation for the term ‘calories in, calories out’ and is a regime that consists of consuming fewer calories than those you burn. It is perhaps one of the most common and popular gateways into the world of weight loss. The idea behind this dietary method is that as long as you’re consuming enough for your body’s essential needs, you can eat whatever you want and lose weight since you’re in a constant calorie deficit. And, for most, it seems to work.

Just one scroll through the CICO diet subreddit will boast hundreds of successful weight loss results, with individuals often using a calorie-tracking app to calculate their necessary caloric consumption. But while it may help you lose weight, that does not mean it’s a perfect method for healthy eating and living. It only works as an approach when people use the method the right way. Every dietary approach comes with a catch, here are four.

According to this method, if you maintain your specific caloric deficit, you can eat anything. So, technically, you could eat chocolate all day as long as you don’t go over your total calories for the day. This concept has caused many to believe that all calories are created equal and that is simply not true. This can lead people to choose eating a packet of crisps over an avocado, because it may contain less calories, even though the nutrients and benefits of the avocado obviously far outweigh the irresistible crisps. Even if this way of eating successfully leads to weight loss, your body could suffer nutritionally.

Sports nutritionist and dietitian Robbie Clark explained to The Huffington Post that the way we metabolise and breakdown the energy from calories is not one-size-fits-all—many factors are at play and different calories (those from unhealthy foods and those from nutrient-dense foods) have different effects on the body.

“Healthy, nutrient-dense foods will keep hunger at bay, help maintain stable blood glucose levels, reduce cravings, and allow your brain to signal to your stomach that it’s full,” Clark said. Whereas, ironically, reaching for those unhealthy foods that may be lower in calories could not only cause obvious nutritional deficiencies, but also lead to weight gain. This is because that unhealthy food choice may not keep you satiated for long.

“Nutrient-poor foods will [thus] have the opposite effect, causing hormonal dysfunction, spiking insulin levels, increasing cravings, suppressing satiety signals and encouraging overeating,” he continued. Things that can’t simply be replaced through supplements. Weight loss in this case doesn’t equate to health. So, if you’re gonna try this method (even though it does work in many ways), be sure to eat as nutritionally as possible within your means.

In order to partake in this regime, calorie counting is an essential element of it, and now, with a stream of fitness-tracking and calorie counting apps, it seems dead easy, right? Not quite. There are a number of factors that can throw off the accuracy of your daily count. Take the example of when you’re eating at a restaurant—can you be certain of the calories in that meal? Have you factored in the effect exercising could also have on your calorie count?

Sometimes when working out over a certain threshold, your body can begin to limit the amount of calories used so that you don’t starve—it’s trying to help you. This is extremely difficult to accurately determine yourself but, perhaps the most common reason for inaccuracy can be the tendency to underestimate calorie consumption. One study found that often people forget what they ate or used in preparing a meal and also don’t account for high-caloric drinks, hidden calories or mindless snacking during the day that may be ingested—this can lead to underestimation of consumption and overestimation of exercise.

Something also to consider is the lack of available food options when filling out your diary on a calorie-tracking app. Often, foods and cuisines from different ethnicities and cultures are not accurately represented—your cultural food is not unhealthy just because an app says so. You do not have to limit yourself to plain chicken breast and broccoli.

Speaking to The Express, Doctor Rupy Aujla expressed his concern on diets such as CICO, “The cons surrounding diets usually boil down to sustainability. When you employ a strategy which reduces calories, a very common dietary method, your weight set-point changes.” This means that when your caloric intake rapidly declines, you may go into what’s known as ‘starvation mode’ whereby your body holds on to as many calories as it can and thus, retains as much fat as it can.

“This is why people tend to plateau, despite having a consistent calorie deficit for a long period of time,” Aujla explained. “This also leads to people falling off the wagon because they are less motivated, usually by the three-month mark, so they will regain the weight they rapidly lost.” Not only are there physical reasons for this being unsustainable but mental ones too.

There is huge enjoyment to be had with food and it is definitely a big influence on your mental health. Living in such a restrictive way could severely impact your mental wellbeing. President of the International Society for Nutritional Psychiatry Research (ISNPR), Felice Jacka, stated that “a healthy diet is protective and an unhealthy diet is a risk factor for depression and anxiety,” and explained that there is huge scientific evidence that shows food is just as important mentally as it is physically.

Counting your calories has long been associated with disordered eating and unhealthy behaviours surrounding food. Beat—a charity dedicated to aiding those with eating disorders—told the BBC as part of its investigation into this association that counting calories, especially aided by calorie-tracking apps, only exacerbate eating disorders and make recovery even more difficult. It also found many harmful entries by MyFitnessPal, Lose It! and Lifesum users that showcased dangerous evidence of binge eating, starvation and severe esteem and mental health decline.