• Rachel Fletcher

Do any diets actually work ?

Have you been on a diet ?

It's January so you can't miss the bombardment of diet and detox loss ads, articles and social media posts but do any of these diet plans actually work ?

How many of you have been on a diet ? I know I have.... There are so many out there, from WW, Slimming World, Keto, Paleo, Noom, GI, Intermittent Fasting, Slim Fast, Detox Teas and don't even go there with the Cabbage Soup Diet - what was that all about ?! This is why the diet industry is worth billions of £ - there's always another diet for you to spend your money on.

It's fair to say that the health industry is very weight-centric and focused on weight loss as a measure of health. However, there are lots of studies that show this approach is actually counter-productive in the long run. I will be writing a separate post about this as it definitely deserves a closer look. Suffice to say, one of the reasons this approach doesn't work is because for most people, dieting doesn't result in long-term weight loss.

How many of you have been on a diet ? How many of you have been on several diets ?

Let's stop and think about this for a minute. If diets DID work, why would you need to go on more than one ? Ok, maybe you tried one and it didn't suit you. So you try another, and another. Is it that you can't find one that suits you and your lifestyle, or is it actually because they don't work...?

Why don't diets work ?

Many people will achieve weight loss in the short-term but continuing those losses, or maintaining your weight at a lower level is much harder. Studies show that less than 20% participants who complete weight management interventions maintain weight loss at 1 year (Jeffrey et al., 2000; Wing & Phelan, 2005,), 63% fail to lose 5% of their body weight using commercial weight loss programmes (McEvedy et al., 2017) and 1/3 to 2/3 of dieters regain more weight than they lost on their diet, ending up heavier than before (Mann et al., 2007).

Why is this ?

Our bodies aren't physiologically designed to be effective on diets. The main reason is that they go into what's known as starvation mode when intake is restricted. This is to conserve energy for vital functions. In time, the body adjusts by slowing the metabolism to burn fewer calories to survive. This impact can continue long after a diet has ended, meaning that when you increase your calorie intake, your body will still burn less off and store fat, leading to weight gain. Research suggests that a 10% weight loss results in a 15% lower than expected level of metabolism (Sumithran & Proietto, 2013). A good example of this is the long-term impact to contestants on 'The Biggest Loser' TV programme, who found even 6 years later that their metabolism was reduced by around 500 calories per day (Fothergill et al., 2016). Many dieters also lose muscle mass when in a significant calorie deficit (Fothergill et al., 2016). Weight loss can also impact our hunger and fullness hormones, meaning we feel hungry more often and full less often. Plus our appetite can change and we definitely start to crave the foods we are restricting, making sustaining the diet really hard (Sumithran & Proietto, 2013). What this means is that biologically, we are always going to struggle with restrictive diets and that isn't your fault. It isn't because you lack willpower, so don't let the diet messaging make you feel bad about yourself.

What about yo-yo dieting ?

Going through periods of restriction, leading to weight loss and then regaining it is known as weight cycling and is associated with a number of health problems. These include cardiovascular disease, high blood pressure, osteoporosis, loss of muscle mass, chronic inflammation and an increased risk of mortality (death rate) (Tylka et al., 2014). There are also psychological effects such as low self esteem, emotional eating and disordered eating.

Does weight loss matter

The first thing I want to stress is that your health is not dictated by your weight. Despite the messaging to the contrary, your health is so much more.... It's about how you feel (your psychological health), how well you sleep, your energy levels, your body image, your physical activity levels, whether you're getting the nutrients your body needs, your immune system (being free from ill health and disease) gut health, to name just a few things. Many studies suggest that your risk of certain diseases and death is actually less with a body mass index (BMI) in the 'overweight' zone. (Although there a ton of issues with BMI that I could write a whole separate post on !)

There are alternative approaches which support improving health outcomes without focusing on weight. These include health at every size (HAES), intuitive eating and mindful eating. Research has shown that these non-diet approaches lead to better overall health outcomes, including lower cardiovascular disease risk, better blood sugar control, a more varied diet, less disordered eating and better psychological health (Clifford et al., 2015).

What should I do ?

I'm going to write more articles about how to ditch the diet mentality, about health at every size, the dangers of yo-yo weight cycling and more about intuitive eating.

However, if you do want to lose weight, I'd firstly recommend being very honest with yourself about why. Is it because you feel that you should because of the diet culture messaging that praises being thin and equates it to being healthy ? Is it because your body image isn't great and you want to feel more confident ? If you honestly want to lose weight for specific health reasons then that's absolutely ok but it's important to understand that it should be done gradually as I hope you now realise, there is no quick fix diet plan that works long-term. Taking things gradually makes it (potentially) more sustainable and will help ensure you're not cutting out food groups and are getting the nutrients you need. It also reduces the risk of going into starvation mode and negatively impacting your metabolism. All of which will help reduce the risk of weight cycling. I would advise seeking professional help with any weight loss plans to make sure you're avoiding these pitfalls and are doing it in the healthiest way possible. This includes your psychological as well as physical health.

Want to know more ?

If this post has resonated with you and you'd like to learn more, sign up to my newsletter to be the first to get my latest articles and resources, including my free download on the side effects of dieting: https://www.subscribepage.com/s6s3x3

Or, get in touch for a free discovery call to talk to me about what you're struggling with and see how I can help you: https://calendly.com/rachelfletchernutrition/15min

You can also learn more about intuitive eating on my other blog posts: https://www.rachelfletchernutrition.com/blog/categories/intuitive-eating


Clifford, D., Ozier, A., Bundros, J., Moore, J., Kreiser, A., & Morris, M. N. (2015). Impact of Non-Diet Approaches on Attitudes, Behaviors, and Health Outcomes: A Systematic Review. Journal of Nutrition Education and Behavior, 47(2), 143-155.e1. https://doi.org/10.1016/j.jneb.2014.12.002

Fothergill, E., Guo, J., Howard, L., Kerns, J. C., Knuth, N. D., Brychta, R., … Hall, K. D. (2016). Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity, 24(8), 1612–1619. https://doi.org/10.1002/oby.21538

Jeffery, R. W., Drewnowski, A., Epstein, L. H., Stunkard, A. J., Wilson, G. T., Wing, R. R., & Hill, D. R. (2000). Long-term maintenance of weight loss: current status. Health Psychology : Official Journal of the Division of Health Psychology, American Psychological Association, 19(1S), 5–16. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/10709944

Mann T , Tomiyama AJ, Westling E , Lew A-M, Samuels B, Chatman J. Medicare’s search for effective obesity treatments: Diets are not the answer. Am Psychol. 2007;62(3):220-233. doi:10.1037/0003-066X.62.3.220

McEvedy, S. M., Sullivan-Mort, G., McLean, S. A., Pascoe, M. C., & Paxton, S. J. (2017). Ineffectiveness of commercial weight-loss programs for achieving modest but meaningful weight loss: Systematic review and meta-analysis. Journal of Health Psychology, 22(12), 1614–1627. https://doi.org/10.1177/1359105317705983

Sumithran, P., & Proietto, J. (2013). The defence of body weight: a physiological basis for weight regain after weight loss. Clinical Science, 124(4), 231–241. https://doi.org/10.1042/CS20120223

Tylka, T. L., Annunziato, R. A., Burgard, D., Daníelsdóttir, S., Shuman, E., Davis, C., & Calogero, R. M. (2014). The weight-inclusive versus weight-normative approach to health: Evaluating the evidence for prioritizing well-being over weight loss. Journal of obesity, 2014.

Wing RR, Phelan S. Long-term weight loss maintenance . Am J Clin Nutr. 2005;82(1):222S-225S. doi:10.1093/ajcn/82.1.222S

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