ANOTHER day, another diet (or another diet headline at least) and this new diet, named CICO for “Calories In, Calories Out” is particularly appealing because you can eat whatever you like and still lose weight.

Well, kind of ...

Sprouted on the Reddit website, it is claimed that the CICO diet works wonders as it allows dieters to eat whatever types of foods they like, in whatever form they want, as long as they consume fewer calories than they burn — the good old weight loss equation.

It quickly became the most popular weight-loss diet on the forum.

In real life food terms this diet suggests you could eat almost all of your entire daily calorie intake via a single fast food meal deal, eat nothing else all day and still lose weight. While this may sound appealing — and may work for those who are significantly overweight (and as such have plenty of extra kilos to lose) and love to eat processed, poor quality food minus any feelings of restriction — for the average person, who wants to drop 5-10kg there are a number of reasons that this approach is unlikely to work long-term.

As such we are likely to see the CICO Diet in the pile of old, useless diets in a few short months.

So here are just some of the reasons it is unlikely you can eat masses of cake, fast food and sugary processed snacks while dropping the kilos.

1. Weight loss is not a one size fits all model

While we often talk about weight loss as a universal concept, the reality is that every single person has a unique set of genes, lifestyle and behaviours that ultimately means the specific variables required for fat metabolism and sustainable weight loss will be different for every single person. For example, an obese 60-year-old male will require a very different dietary approach for weight loss than a slim 60kg female who only want to lose a couple of kilos and who already exercises. Each different metabolism will respond differently to different diets and while some individuals may get initial results watching and cutting back on their calories, for others this strategy will have no observed effect.

2. It is easy to go overboard with calories

The CICO Diet sounds appealing — eat cake and lose weight but it is important to remember it is difficult to keep daily calorie intake controlled when high calorie, processed foods including fast and fried foods, cakes, biscuits, chocolates and pastries are being consumed. With the average adult needing only 1500-2000 calories per day, and a single slice of cake containing up to 800 calories, or a fast food meal more than 1000 calories, just one or two of these “allowed” foods will completely wipe out your daily calorie total. This means that for the CICO Diet to work, dieters are also going to have to focus on low calorie foods, which actually sounds a lot like any regular diet.

3. All calories are not equal

The most farcical aspect of the CICO diet is that it assumes that all the calories we consume are metabolised equally in the body, which is not the case. For example, calories consumed as added sugars are more likely to result in elevated insulin levels, which can result in fat storage over time. While fat is always preferentially stored when consumed in the presence of carbohydrates and higher protein foods will contribute to satiety and lower levels of insulin over time compared to more processed carbohydrates. The timing of meals is too important — a large number of calories consumed during the first half of the day is very different than if they were consumed at night. These intricacies of diet specificity means that when individuals need to lose large amounts of weight, calorie deficits will be effective, but long term macronutrient quality and meal timing will too need to be considered.

4. Hormones are often involved

A calories in versus calorie out dieting approach also ignores the fact that a number of hormonal disruptions linked to weight gain including leptin and insulin resistance significantly disrupt the body’s natural fat metabolism cycle. For these groups it may mean that their cells are not as efficient in burning carbohydrates and fats and as such actually need fewer calories and / or carbohydrates to effectively burn body fat. This means for these groups, a mere calorie deficit may simply not be enough to support sustainable weight loss.

5. Weight loss does not mean health

While calorie intake is important for weight control, of greater importance is the need for a range of unprocessed, natural whole foods to be consumed for good health — the body does not only require calories, it requires a range of macro and micro nutrients each and every day to function at its best. Eating a diet packed full of processed foods that still results in weight loss may sound great, but over time it will impact your general health, energy levels, mood and how you look and feel. A diet that only focuses on calories completely ignores the importance of a range of foods for good health and well-being overall.