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Why diets fail by Karina Melvin

Why Diets Fail: 4 Effective Psychological Strategies to Achieve Lasting Weight Loss

The truth about why diets fail

Did you know that average caveman had to run 16 kilometers a day to catch his prey? Unfortunately, we are no longer moving even half as much as that, with an increasingly sedentary lifestyle dominating in western society.

Today 44% of the diabetes burden and 23% of the heart disease burden up to 41% of cancer burdens are linked to obesity. In the U.S.A 75% of adults are overweight. We are currently living in a time where obesity kills more people than starvation.

There is a common misconception out there that losing weight is easy if you just eat less and move more. But this is an over simplified premise and is one of the central reasons for why diets fail. If calories in is less than calories out, you lose weight right? While physiologically this is correct, human subjectivity is far more complicated than that. There are so many misconceptions and assumptions about how easy it is to lose weight.

A recent survey asked dieters, ‘what weight loss are you aiming for ?’ The average dieter wanted to lose about 25 kg. After 12 months of eating less the dieters had lost on average 6kg (8kg with exercise). This is a lot less than you would expect. Out of everyone that started out only 50% were still making the effort to lose weight after 12 months. Unfortunately our expectations do not align with reality. They are perpetuated by the media and lose weight fast programs as we try to lose weight with sheer power alone. So we set ourselves up to fail.

A further complication has emerged from research conducted by UCLA which was reported in the American Psychologist,  is that once we lose the weight we gain at least some, if not all of it back.

“You can initially lose 5 to 10 percent of your weight on any number of diets, but then the weight comes back,” said Traci Mann, UCLA associate professor of psychology and lead author of the study. “We found that the majority of people regained all the weight, plus more. Sustained weight loss was found only in a small minority of participants, while complete weight regain was found in the majority. Diets do not lead to sustained weight loss or health benefits for the majority of people.”

Mann and her co-authors conducted the most comprehensive and rigorous analysis of diet studies, analyzing 31 long-term studies.

So weight gain has some serious physical health consequences and it is very challenging to maintain weight loss,  but what about the psychological consequences?

We need to stop ignoring the psychological aspects of weight loss. 

To lose confidence in one’s body is to lose confidence in oneself.

I had a client who was carrying over 50 extra pounds of weight and she just couldn’t enjoy the good things in life. She couldn’t enjoy a special occasion, or getting dressed up. She hated going to weddings and having to shop for clothes that fitted her. Emotionally she was struggling and ultimately she was depressed. There are so many people who are severely unhappy with their body and yet they struggle to lose the weight.

Why diets fail, from a psychological perspective

1.Most diets are structured around deprivation 

‘I’m not going to eat the thing that I want because I am trying to lose weight’.

This is a position of punishing yourself and eventually you are going to cave in and eat the thing you love, because we are fighting against the ‘pleasure principal’. This is the fact that we are hard wired to experience pleasure and avoid pain, so prohibiting the things we love to eat simply will never work. Going against this basic human instinct is one of the main reasons why diets fail, often quite quickly.

2.We rely on self control 

We have this idea that if we have enough will power weight loss would be easy.

But what psychological research tells us is that we only have a finite amount of self control. Think of will power like a muscle, when you use it, you get tired. And that’s what happens with self control: when you exert self control you become fatigued, this is what’s known in psychology as ‘ego depletion’. When we experience ego depletion we are less able to use self control again. So we give in or give up! This is one of the core reasons for why diets fail.

3. When dieting we rely on the psychology of thought suppression or what’s known as the ‘white bear effect’.

What this simply means is if your told not to think about a white bear, what do you end up thinking about? A white bear!

It works the same way with a craving for a food you want. If you tell yourself ‘I can’t have that cheese burger, it’s really bad for me’ then all you can think about is the cheeseburger.  This happens because when we try to suppress a thought, on a preconscious level we then must scan for the thought that we are trying to suppress and that means that we have to be aware what the thought actually is. So it keeps popping up in our consciousness and then we have to keep repressing it. This is a very tiring to do and why diets fail!

So when you’re trying to lose weight and the cheeseburger thought keeps popping up its important to acknowledge the thought. Say to yourself ‘tonight I’ll have a cheeseburger’.  You must indulge your thoughts and cravings in a positive way. You can have the cheeseburger, tell yourself ‘I’m going to make it myself and it will be full of healthy non-processed natural good quality ingredients and it’s going to taste fantastic’.

Psychological research has found four key factors behind successful weight loss:

1. Don’t view your weight loss approach as a diet

People who successfully lose weight and maintain the weight loss do not undergo deprivation & self punishment because this is not sustainable in the long term. They do not battle with themselves on a daily basis to stave off foods they love. 

2. See it as a positive lifestyle change

So think about making changes in your life, to the way you think and the way you behave. Successful weight loss is about treating your body well and with positivity and kindness. Its about improving your life, not just losing weight.

3. A personalized approach works best

Eat the foods that you like and do the exercise that you enjoy. Make sure it fits it into a schedule, commitments and preferences that work for you. That is why I don’t encourage my clients to prescribe to any specific food program, you should eat anything you like as long as you seek out the best quality you can afford and eat when you feel hungry.

4. To achieve successful weight loss and to maintain it, you need the right supports.

The right advice and the right strategies to deal with things that make weight loss difficult from a psychological stand point is essential. You need to be taught the right cognitive skills, you need to have enough leverage to commit to achieving your goal. You also need the right emotional and environmental supports.

Diets don't work by Artful EatingFind out more about why diets fail! To learn more about Artful Eating: the psychology of lasting weight loss, an approach where I will share with you the skills and tools to lose weight, enjoy food and achieve your dream body without the pain and restriction of dieting, check out my free training Artful Eating: Reprogram your mind to transform your body. 


Why Diets Fail: 4 Effective Psychological Strategies to Achieve Lasting Weight Loss

Karina Melvin, MSc, MA

Karina Melvin provides online psychoanalysis and counselling services from her South Dublin office with her team of high-level psychoanalysts. You can learn more about online counselling, psychoanalysis by clicking the link below.

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APA Reference
Melvin, K. (2016). Why Diets Fail: 4 Effective Psychological Strategies to Achieve Lasting Weight Loss. Psych Central. Retrieved on July 9, 2020, from


Last updated: 24 Oct 2016
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