Why Diets Don’t Work (and 6 Steps to Take Instead)

Whether it’s a convincing ‘before and after’ photo or a friend who is raving about their latest diet, it seems like everyone has the answer to losing weight and keeping it off. But why is it so hard for most of us to sustain intentional weight loss? Is it a lack of willpower? Are we just not trying hard enough? Or is there more to the story that the dieting industry doesn’t want us to know. As an intuitive eating dietitian, I’m here to set the record straight on why diets don’t work, why it’s not as simple as calories in vs. calories out, and what to do about instead.

Have you ever “successfully” lost weight on a diet plan, only to regain the weight back? Do you wonder why the first diet you tried “worked” so well, but you just can’t seem to get the same results, if any at all? 

If you’ve ever felt like a failure because you couldn’t stick to a diet, you’re not alone. In fact, research shows that 95% of dieters regain their lost weight within 1 – 5 years, with up to ⅔ of those dieters regaining even more weight than when they started. 

So what does this mean? 

It means that this isn’t a matter of the vast majority just not having the willpower or discipline to lose weight and keep it off, it’s a matter of participating in a system that is set up to fail. 

If diets truly worked, the 72 billion dollar diet industry would tank overnight because there would be no repeat customers.

We often refer to the dieting industry as one of the biggest gas lighters out there, as it sells you a faulty product and then makes you think it’s your fault when it doesn’t work.

As an intuitive eating dietitian, I want to make sure you are well armed with the facts. Here we do a deep dive into what a diet is, the research behind why diets don’t work long term, and 6 things to do instead.

Off the top, we often hear these two questions come up time and time again:

You can also skip to any of the following parts of the article at the links below! 

• What is a diet?
• Why diets don’t work?
• Why am I not losing weight even though I exercise and diet?
• 6 steps you can take instead of dieting

What is a diet?

A diet can be described in 3 ways: 

1. The kind of food that a person or community habitually eats 

2. A medically necessary diet that may be recommended and guided by a health professional (ex. A gluten free diet for celiac disease or avoiding a certain food due to an allergy) and 

3. Making the personal choice to intentionally restrict or manipulate one’s food intake with the sole intention of losing weight or preventing weight gain. 

In this article, we will be referring to the third definition of a diet. While there are many fad diets on the market, a way of eating can be considered a diet if it includes some or all of these disordered eating behaviours:

• Cutting out whole food groups
• Ignoring/delaying hunger cues
• Consistently eating less than your body needs
• Fluid loading with water or coffee to stave off hunger 
• Compensating for eating with overexercising, fasting, or purging
• Obsessive calorie counting (if this resonates with you and you’re looking for support, check out ‘Why Calorie Counting Doesn’t Work’)
• Eating according to a set of rules regarding when you can and can’t eat, as opposed to listening to your own body

Why diets don’t work?

You may be wondering “but aren’t there crash diets that work? It worked for (insert someone you know), shouldn’t it work for me?” And this makes sense, considering the internet is riddled with convincing ‘before and after’ photos that make you buy into the weight loss fantasy. But let’s dive into the research.

Research shows that diets don’t work for the vast majority of dieters, regardless if they stayed on the diet or not

A key study that highlights the unsustainability of intentional weight loss is seen in the Women’s Health Initiative, one of the largest and longest randomized controlled diet interventions. It followed 20,000 women between the ages of 50 and 79 who maintained a low fat, calorie restricted diet for the duration of 9 years. During this time, they were asked to keep track of their diet including how many servings of fruits, vegetables, grains and fats they had each day during the study.

Looking at this graph, we can see that initially in the first year of making dietary changes, the women lost weight (as shown with black dots). However, even though these women diligently maintained their diet and tracked their intake over the course of this study, we can see that over 9 years there was virtually no difference when compared to their starting weights.

Human beings are wired for survival

Humans have learned to adapt and survive instances of famine for millions of years. In terms of the ‘survival of the fittest,’ our ancestors who were able to pass on their genes were the ones whose biology had evolved to fight tooth and nail when the threat of starvation hit. As a result, we now see changes within the body that encourage weight regain after diet induced weight loss. These include changes to energy expenditure, metabolism, and hormones that are involved with appetite regulation, and can continue long after the initial weight loss period. 

As described in Traci Mann, PhD’s book ‘Secrets From the Eating Lab,’ there are 3 biological changes that occur in response to dieting:

1. Neurological changes:
   • Dieters are more likely to notice food, especially tasty looking food, and food registers as more appetizing, tempting, and rewarding. Interestingly, in one of her experiments, they found that when distracted, dieters consistently ate more than non-dieters. They also noted that distraction only seemed to increase the intake of the dieters, but not the non-dieters.

2. Hormonal changes:
   • In response to calorie restriction and weight loss, we see our leptin levels (our satiety hormone) along with hormones PYY, CCK, insulin and amylin drop – which poses a challenge as they all play a role in inhibiting food intake when we are in the fed state. Ghrelin (our hunger hormone), on the other hand, increases during calorie restriction. This means that we’re more likely to feel hungry and less likely to feel full given the same amount of food.

3. Metabolic changes:
   • In efforts to keep us safe, our body slows down our metabolism and starts to use calories in the most efficient way possible. While this is a good thing to help prevent us from starving to death, it directly undermines one’s efforts to lose weight. In other words, as the body finds a way to run on fewer calories, there may be more calories leftover which may in turn be stored away as fat. 

The Dieter’s Dilemma, AKA the Diet Cycle

Another concept that shows why diets fail is ‘the Dieter’s Dilemma’ (diagram above was pulled from the Intuitive Eating book, by Evelyn Tribole, RD and Elyse Resch RD). This diagram was created by two psychologists, John P. Foreyt and G. Ken Goodrick. This cycle is triggered by the desire to be thin (as influenced by diet culture), which leads to dieting and restriction, which then leads to insatiable cravings and reduced self control, resulting in rebound loss of control eating, and ultimately ending with regaining the lost weight. Each turn of the cycle often leads us back to square one, having regained the weight back and often plus more.

Why am I not losing weight even though I exercise and diet?

As we’ve seen in the sections above, the idea of weight loss as a matter of calories in vs calories out can be considered a major oversimplification of how our body regulates our metabolism. While it’s easy to lose weight in the short term, in the long term the body has compensatory mechanisms that undermine its ability to maintain weight loss. Studies show that although exercising increases calories burned, the body will still try to maintain its set point weight, by increasing one’s appetite and manipulating it’s metabolism. Additionally, long term studies show that the vast majority of people are unable to maintain significant fat or weight loss by increasing their physical activity, even when they maintain their increased exercise routines.

Ok so we don’t’ want to just be downers and leave you hanging but if this isn’t compelling evidence to let go of dieting, I don’t’ know what is…so what can you do instead?

6 Steps You Can Take Instead of Dieting

Practice mindfulness

Take a moment to pause and reflect on where these dieting beliefs came from. What food rules are you following and are they leading you closer to, or further away, from how you truly want to feel? Consider what tastes good, feels good, and what satisfies you. Building self awareness around your eating habits is the first step towards lasting behaviour change and developing a healthy, feel good relationship with food!

Focus on health promoting behaviours

Try your best to put weight loss on the back burner for now, and focus on the behaviours that feel good, both physically and mentally. This includes letting go of dieting rules as a way to impose self control and instead exploring healthy eating habits that feel good to you as a gentle way to nourish your mind, body, and spirit. Other behaviours include focusing on adequate sleep, stress management, social connection, and joyful movement. 

Reconnect with your body’s wisdom

The longer we live in our heads and abide by external food rules, the further disconnected we become from our bodies. Connecting to how hunger and fullness actually feels to you can be a powerful tool to learning to trust yourself with food again. Using the Hunger Fullness Scale might be a great place to start.

Give yourself unconditional permission to eat all food

If you’re tired of Feeling Guilty After Eating, it’s time to give yourself permission to eat all foods. This may sound scary, but remember, it’s restriction that makes us feel out of control with food. Once we remove restrictions, we are able to remove guilt, and explore all of the many ways we can make food feel good.

Cultivate Body Respect

Body respect isn’t loving or even liking your body, but it’s treating your body with dignity and meeting its most basic needs: enough food, water, warmth, and rest. 

Foster body acceptance

If you’re noticing big emotions coming up when you think about giving up the thin ideal or the weight loss fantasy, you might be grieving body acceptance is worth exploring. We were first introduced to this concept by Meredith Noble who wrote the amazing article ‘Body Acceptance Begins with Grieving the Thin Ideal’. Here she describes how the body acceptance process can mirror the five stages of grief, with added advice on tangible steps for each phase. If this resonates with you, it may be helpful to process through this with a trusted therapist or health professional.

Now Over to You

• Did anything about the research surprise you?
• What diets have you tried in the past? 
• Which of the tips above would you be open to trying as an alternative to dieting?

Share with us in the comments below or take a screenshot and share it with us over on Instagram! And if you found this post helpful, pass it along to a friend or family member who could benefit from it too!

Looking for More Support?

Looking for support to end the diet cycle, trust your body and learn the nutrition that feels amazing for YOU? Learn more about my Make Food Feel Good Program here where hundreds of women have found lasting success through my proven framework and step-by-step guided support. Let’s Chat!