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The truth about fad diets

Why it's time to ditch them for good

We’ve all seen the tempting adverts – whether it’s ‘Lose weight fast’, ‘Drop 10kgs in 2 weeks’ or ‘The weight loss secret celebrities swear by’ – those quick and easy results many diets claim to deliver can be hard to ignore. But it’s important to remember that these fad (or crash) diets are usually based on unrealistic eating – often restricting the food you can eat or even cutting out some food groups entirely, often without a scientific basis. Find out why these diets are not sustainable and what’s better for your physical and mental health in the long run.


What’s so bad about fad diets?

In a nutshell, fad diets achieve rapid weight loss through extreme kilojoule restriction. So, while you may see the ‘quick results’ promised, this initial weight loss is actually mainly due to water loss.

Restricting the type of food you eat is also linked to food cravings and feeling hungry as your body looks for the essential energy and nutrients it needs. Your mind also seeks to find the comfort or normality it is used to in particular situations, likely associating eating with particular activities such as watching TV, making it a mental challenge too. So, while limiting what you eat may achieve some short-term weight loss, in the long run these restrictive diets are not sustainable either mentally or physically, and your weight is likely to rebound (often to a higher weight than when you began!). To put it simply, there’s no quick fix.

It’s also important to know that, just as detrimental as the physical effects, fad diets can negatively impact your mental health. Cutting out certain food groups or not eating enough food overall is mentally draining and difficult to maintain, so there’s often a ‘breaking point’ that can lead to feelings of disappointment and failure – which can then lead to unhealthy eating.


Slowing down your metabolic rate (the science bit!)

The process of converting food into energy that’s used to fuel the body is called your metabolism. Your Basal Metabolic Rate (BMR) is the energy (kilojoules) your body needs at rest, to do things like breathe and pump blood around your body. Fad diets can interfere with your metabolic rate as your body can go into a state of starvation and protect itself by maximising every kilojoule you eat (probably not the result you were after!).

The best way to maintain your metabolic rate is by exercising regularly and losing weight gradually.


What’s a better plan for weight loss?

First things first. For weight loss to be sustainable you need to know what a healthy weight is, so it’s a good idea to chat to your GP or an Accredited Practising Dietitian before starting any diet so you know what’s appropriate and achievable for you. If it’s recommended you cut back your energy intake (the kilojoules you consume from food and drinks) to reduce your weight, do so in stepped increments and at the same time increasing how much energy you use through moving (physical activity), again in small manageable steps. A modest goal of losing 5-10% of your starting weight is realistic, achievable and has proven health benefits1.  

Identifying and gradually changing unhealthy habits, in a way that is enjoyable and fits with your lifestyle, will make the healthy habits easier to maintain. So, while it may take longer to see the results you want with this approach, it’s more likely you’ll maintain a healthy weight long term.  Remember, there is no ‘one-size-fits-all’ solution to weight loss and an Accredited Practising Dietitian can help tailor a weight loss plan that works for you.


What should you be eating?

Eating a variety of nutritious food is the key to staying healthy and reducing the risk of chronic disease. Remember that the food you eat directly impacts your energy levels, immune system, heart health, cancer risk and mental health, so making good nutrition a priority will pay off in more ways than one.

The amount of each food group you need depends on your age and gender (so check in with your health professional if you’re unsure). The Australian Dietary Guidelines (ADG) recommend eating a variety of foods from each of the five food groups: vegetables, fruit, grains, meat and alternatives, and dairy and alternatives, and limiting discretionary food and drinks (the ‘sometimes foods’!) which are high in kilojoules and low in nutrients.


Tips and strategies

We’re all different and the key to sustainable weight loss and maintaining a healthy weight is figuring out what works for YOU. Here are some tips to get you started:

  • Speak to an expert – before starting any weight loss plan, it’s a good idea to check in with your GP to see if you have any dietary deficiencies. A health professional like an Accredited Practising Dietitian can help design a tailored, individualised eating plan to meet your goals and support you to stay on track. They can also help you identify the emotional and motivational factors that really drive your food decisions, to set you up for success.
  • Understand your needs – any diet and exercise plan must suit your needs if it’s going to be sustainable, so it’s important to know exactly what your goals are.
  • Be realistic – setting goals that are achievable will help you stay positive and keep you motivated to continue your weight loss plan.
  • Take control – self-monitoring and evaluating your dietary intake helps you to understand your behaviours and identify if any changes need to be made. Keeping a record of what you eat and your physical activity can make it easier to stay accountable and help you be more mindful regarding eating and activity choices.
  • Get a big picture view of health – don’t rely on short-term weight loss and restricting your food intake, changing your habits is the key to sustaining a healthy weight.
  • Eat a varied diet and stay hydrated – while reducing energy intake is part of the solution, dietary change will be easier to sustain if you focus on eating nutritious foods which will help keep you feeling satisfied. Being dehydrated can make you feel tired and hungry, so try having a glass of water before snacking.
  • Protect your metabolic rate – extreme food restriction interferes with your metabolism and can lead to weight gain, so ditch the fad diets and set low and slow weight loss targets instead.
  • Address any negative emotions – be kind to yourself! You’ll have good days and bad days but don’t give up – be your own support coach.


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