Crash diets don't work: Here's why

This is the time of year when many people embark on fad diets and can often end up on this roller coaster going from one diet to another feeling miserable, hungry and tired. Diets are about what you ‘can’t’ have, what you ‘can’t’ eat, making life all very negative.


The diet industry makes millions of pounds and they are banking on your diet failing to keep the industry going. Ridiculous? Yes. Ethical? No.

A recent study followed people for two years after their diets and found that 83% of them gained back more weight than they initially lost. 

Why don't crash diets work?

In evolutionary terms, the human body is designed to maintain your weight and is hard-wired to do this. Crash diets don’t work long term. Fact.

  • Crash diets are not sustainable and are low in calories.
  • Diets are often boring as your food choices are heavily restricted.
  • Dieting can cause elevated levels of cortisol which can promote weight gain.
  • They can sometimes cut out entire food groups, which is not healthy and can lead to nutritional deficiencies and long term health issues.
  • Often you are losing water or muscle weight.
  • Body metabolism slows down to adjust to the restricted calories and rather than go into fat-burning the body can go into fat storage mode.
  • Crash diets don’t address any emotional and mindset issues.
  • Dieting can make you ‘food-obsessed’ and food can be seen as a reward.
  • Weight loss and happiness are two different things.
  • Will power alone often isn’t enough to keep you on track.

It’s important to note that losing weight will also not necessarily make you ‘healthier’. Dieting is stressful and does not teach you to eat healthily.

In the short term, you may look at the number on the scales and you may have lost weight and think the diet is working but any initial dramatic weight loss is often down to fluid loss. It is not a clever way to try to lose body fat as your metabolism slows down and you produce more of the hunger hormone (ghrelin) and less of leptin (the hormone that regulates fat storage) as your body attempts to cope with fewer calories. 

These crash diets are often boring as your food choices are heavily restricted. After some rapid weight loss initially, these diets are not sustainable as you will end up putting the weight back on, and often more.

They set you up for failure and disappointment.

Not to mention that they leave you feeling miserable, undernourished, grumpy, tired, weak, unhappy, frustrated even depressed and can result in insomnia, poor concentration, lower energy levels and poor brain health.

In terms of your brain health, due to these diets being very low in calories and essential fats and, as your brain can only use glucose as an energy source, your concentration and brain health will suffer, as well as putting yourself at risk of developing nutritional deficiencies. 

So, in order to achieve and maintain health for the long-term, you need to adopt healthy habits lasting a lifetime and think about what you can have so turn eating into a positive experience.

So, here are my five top tips for long-term healthy eating and avoiding crash diets.

1. Plan ahead

You know what you are going to eat and sometimes making the decision when you are hungry and tired can be where it all goes wrong.

Porridge breakfast bowls

2. Eat breakfast and never skip meals

To help keep hunger at bay and balance your blood sugar levels, ensure food consistency. Research shows that people who eat breakfast tend to have a more balanced diet overall. So, start your day with a healthy breakfast which includes protein e.g. eggs or porridge with nuts and seeds, which will avoid you becoming overly hungry.

3. Portion control

This is an important part of maintaining a healthy diet especially when it comes to weight loss. Take a look at your portion sizes as it can be possible to eat too much of a good thing.

4. Exercise

Regular exercise will keep your metabolism high. Exercise is key for weight loss as it can help improve glucose metabolism and insulin sensitivity, burning calories while reducing abdominal fat.

5. Prioritise your sleep

Sleep also plays a critical role in weight management as it controls the hormones that regulate metabolism and appetite. With poor sleep, leptin levels fall which can cause constant feelings of hunger and ghrelin levels rise causing an increased appetite so can cause you to overeat.

Finally, getting the right help and having the right mindset is key to maintaining a healthy weight and optimising your long-term health and happiness. For long term success, think of your well-being in terms of adopting a healthy lifestyle rather than being on a diet so that you glow and feel good from the inside out.

The ‘30-day feel great challenge’ is the ideal opportunity for you to receive my expert support, without the overwhelm, and banish unhealthy habits once and for all!

It follows my ethos of ‘small steps approach’ to changing habits to nourish you whilst at the same time supporting your mental health. If you know me, you’ll know that I have a no-nonsense approach to health and that I’ve helped many clients eat and live well. 

Why not enter into 2021 with some support so you can really glow?

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

Share this article with a friend
Show comments

Find a nutritionist dealing with Healthy eating

All nutrition professionals are verified

All nutrition professionals are verified