Eight reasons why your fad diet isn't working

If you're following a fad diet and not feeling great - it's not your fault. Many fad diets operate on the basis of removing or emphasising certain foods over others, and this can create nutrient deficiencies. For instance, going hardcore vegan means you may have to supplement with iron and B12, or going hardcore ketogenic might mean you become deficient in fibre. When the body falls low on a certain type of nutrient, it'll quite often slow the entire system down and give you a feeling of lethargy.

Yes, we've all heard of the now-infamous "30 bananas a day diet", and here's why it makes you feel terrible: not only does it fail to account for the wide variety of nutrients you need in your body, it often fails to account for calories. While a 50kg, untrained female girl might survive okay on 30 bananas a day, a high-performing athlete certainly couldn't. Fixating on including - or removing - one particular food is in no way sustainable over the long term.

While tracking your calories and macronutrients is important to know the sheer volume of food you're eating, if your fad diet doesn't allow for periods for flexibility then it's likely to steer you towards obsessiveness. If you find yourself expressing shame or disgust in marginally breaking your diet or eating just a few calories extra, then you may have a disordered eating pattern.

Many people take up fad diets - like week-long juice cleanses or drinking nothing but saltwater - in order to fix problems with their body that aren't strictly related to their weight. For instance, if you feel that your gut is malfunctioning you may have a food intolerance, or if you can't get to sleep you may have become extremely sensitive to caffeine. To address the underlying problem, your best bet is to book in with a dietitian or start a very gentle and moderate elimination diet.

Most fad diets give you considerable weight loss within the first week - that's part of the reason why they're so popular. But generally this weight loss is down to two things: your new diet is low in sodium and has caused you to shed "water weight", or it's simply so low in calories that your body has radically begun to dip into its reserved energy stores. In both instances you'll find that you'll be lighter on the scale but feel absolutely terrible - making the whole diet not worth attempting in the first place.

Many people focus heavily on losing weight, when really they should be concentrating on improving their body composition (which is the amount of muscle you have relative to fat). In order to do this, you'll need a bucket-load of energy to pour into a combination of resistance and cardiovascular exercise - and sipping nothing but juice ain't going to cut it. Forget about what the number of the scale is, and focus instead on your performance - you'll be shocked to find your body will follow suit.

Some people can get so involved in the "theory" of the latest diet that they forget it's totally possible to still get fat from eating healthy food. For instance, many people who jump on board the paleo bandwagon go nuts on bacon, heavy cheeses and olive oil - and if they aren't careful these calorie-dense fats could push you over your daily limit. The same happens with intermittent fasting, because the human mind tells you it's okay to binge because you haven't eaten for half a day.

There's a simple solution to all of this: you need to find a way of eating that gives you nutritious foods that you enjoy. If a fad diet feels in any way torturous or hard to follow, then its days are numbered in terms of how long you'll be able to keep it up. Instead of searching for a diet that will give you the quickest results, look instead for the tastiest way to be healthy - your waistline will thank you in the long run.