Opinion: Diets don’t work! Here’s why

Hayley Brock, Nutrition Student

The U.S. weight loss and diet industry reached a record worth of $78 billion in 2019 and the global weight-loss industry is expected to be worth $278.95 billion by 2023.1 Is the diet industry so profitable because diets work? Or because they don’t? 

Research shows that up to 95% of all diets fail—meaning that the individual may have gained all the weight lost back, and then some. In a meta-analysis of 29 long-term weight-loss studies, more than half of the weight lost was regained within two years, and by five years more than 80% of the lost weight was regained.2 It’s not losing the initial weight that’s unsuccessful, but keeping the weight off. In part, we have our bodies to thank for that.

When we lose weight and body fat, our metabolisms can also drop and work less efficiently. Even if you regain the weight back, your metabolism may not catch back up. This means that the body at rest will burn fewer calories than it used to.3 This is best highlighted by the Biggest Loser study. Participants that were on the show The Biggest Loser became much more efficient at utilizing calories by lowering the body’s need for energy (decreasing metabolism), and this effect persisted for six years after dieting!3 Additionally, as an individual loses weight their body adapts through mechanisms that increase appetite and decrease satiety (fullness). One study even found that the body will prompt us to eat an extra 100 calories for every 2 pounds of weight that we lose!4 This means that the more weight you lose, the hungrier you become. Our bodies are almost conspiring against long-term weight maintenance! 

Not only are our bodies biologically wired to fight back against weight loss and diet restriction, but so are our minds. A diet is a period of food restriction that puts your body into a state of deprivation. Deprivation is not just from calories but from foods you love and even activities you may enjoy. Anyone with a child knows, when you tell them “no, you can’t have that”, they want it even more! The same thing goes for a dieting body. This is why it’s so hard for an individual to stick to a period of strict restriction. The restriction period (weight loss) often leads to a binging period (weight gain) and the cycle is repeated constantly throughout the life of a dieter! Psychologists call this the “Dieter’s Dilemma”. The Dieter’s Dilemma starts with a desire to be thin, which leads to dieting, which leads to cravings and reduced self-control, which leads to loss of control and overeating, which leads to regaining of lost weight, and again back to the desire to be thin and starting the whole malicious cycle over!1 

Instead of focusing on weight loss, many health professionals and researchers are calling for a paradigm shift towards a behavior change focus.5 Weight is not a behavior, and thus should not be the focus of behavior change strategies. Instead of focusing on how quickly the body can lose weight, focus on how to make the body feel its best. Simple ways to step out of diet culture and into true health and wellness can include: engaging in movement you enjoy, focusing on adding beneficial foods to the diet instead of taking foods away, and shifting away from using the scale as your main measure of progress.


  1. Tribole E, Resch E. Intuitive Eating: A Revolutionary Anti-Diet Approach. 4th ed. New York, New York: St. Martin’s Essentials; 2020.
  2. Anderson JW, Konz EC, Frederich RC, Wood CL. Long-term weight-loss maintenance: a meta-analysis of US studies. Am J Clin Nutr. 2001;74(5):579–584. Doi: https://doi.org/10.1093/ajcn/74.5.579 
  3. Fothergill E, Guo J, Howard L, et al. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity (Silver Spring). 2016;24(8):1612-1619. Doi: https://doi.org/10.1002/oby.21538 
  4. Polidori D, Sanghvi A, Seeley RJ, Hall KD. How strongly does appetite counter weight loss? Quantification of the feedback control of human energy intake. Obesity (Silver Spring). 2016;24(11):2289-2295. Doi: https://doi.org/10.1002/oby.21653 
  5. O’Hara L, Taylor J. What’s wrong with the ‘War on Obesity?’ A narrative review of the weight-centered health paradigm and development of the 3C framework to build critical competency for a paradigm shift. SAGE Open. April 2018. Doi: https://doi.org/10.1177%2F2158244018772888


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