Why Most Weight Loss Diets Fail: And What Actually Works

Let’s face it—most of us have tried a diet at some point, hoping it would finally be the one that works. Maybe it was low-carb, high-protein, keto, or something your favorite influencer swore by. And for a little while, it might have worked. But then, somewhere along the way, the scale stopped moving, motivation slipped, and old habits crept back in. Sound familiar?

This article explores why so many weight loss diets end in frustration—and more importantly, what actually makes them work in the long run. Why weight loss diets fail is not about choosing a diet. It’s not about finding the “perfect” diet. It’s about understanding what our bodies and minds really need to make lasting change. The answer might be simpler—and more sustainable—than you think.

It is well established that being obese or overweight is a major modifiable risk factor for heart disease (Benjamin et al., 2019; WHO, 2021). Beyond heart disease, being obese or overweight has been associated with a plethora of other chronic diseases, including type 2 diabetes, high blood pressure, certain cancers, cholesterol abnormalities, metabolic syndrome, fatty liver, endocrine disorders, infertility, osteoarthritis, and sleep apnea (Pi-Sunyer, 2009; Hruby & Hu, 2015). And I am sure there is more to come.

On top of the destructive effects overweight has on our health, there is the social stigma attached to being overweight or obese. This is no small matter when it comes to a person’s quality of life. Often, our weight can affect acceptance into social groups, whom we date, and, in extreme cases, the work we do (Puhl & Heuer, 2009; Latner & Stunkard, 2003).

Often, we hear of people going on a variety of weight loss diets, each one touted as being more effective than the other. Then, the diet fails. Or does it? Scientific evidence indicates adherence is the most important factor when it comes to success or failure of weight loss diets. It matters not, it seems, whether we embark on a low-carb diet, a low-fat diet, an Atkin’s diet, an Ornish diet, a high-fat diet, a keto diet, or a high protein diet. We can achieve healthy weight loss with either of these if we stick to the diet (Gardner et al., 2018; Johnston et al., 2014).

The success of any diet rests on a reduction of the daily calorie intake. Our intake of calories must fall below the daily energy expenditure for there to be weight loss. A reduction of 500 kcal/day will produce a total loss of 3500 kcal in one week. This is the approximate number of calories contained in one pound of fat. At this rate, we can expect to lose one pound per week (Hall et al., 2011; Thomas et al., 2013).

So, what can we do to ensure adherence to our diet? Most people have difficulty sticking to unnatural practices. By unnatural, I mean practices they are not accustomed to. If your diet required you to eat while walking around, for example, most people would eventually abandon such a diet. On the other hand, if you were raised eating while walking around, you would never sit to eat.

This is where lifestyle comes into play. Our adherence to the diet we choose depends on how quickly the diet becomes a part of our lifestyle. A healthy diet must become an intricate part of our lifestyle. A healthy lifestyle must encompass a healthy diet. Everything else must feel alien to us (Wing & Phelan, 2005; Knowler et al., 2002).

References

Benjamin, Emelia J., Michael J. Blaha, Stephanie E. Chiuve, Mary Cushman, Sandeep R. Das, Rajat Deo, Sarah D. de Ferranti, et al. 2019. “Heart Disease and Stroke Statistics—2019 Update: A Report from the American Heart Association.” Circulation 139 (10): e56–e528. https://doi.org/10.1161/CIR.0000000000000659.

Gardner, Christopher D., Matthew J. Trepanowski, John W. Del Gobbo, et al. 2018. “Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association with Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial.” JAMA 319 (7): 667–79. https://doi.org/10.1001/jama.2018.0245.

Hall, Kevin D., Steven B. Heymsfield, Joseph W. Kemnitz, Samuel Klein, Dale A. Schoeller, and John R. Speakman. 2011. “Energy Balance and Its Components: Implications for Body Weight Regulation.” The American Journal of Clinical Nutrition 95 (4): 989–94. https://doi.org/10.3945/ajcn.111.013052.

Hruby, Adela, and Frank B. Hu. 2015. “The Epidemiology of Obesity: A Big Picture.” Pharmacoeconomics 33 (7): 673–89. https://doi.org/10.1007/s40273-014-0243-x.

Johnston, Bradley C., David A. Kanters, Joanne A. Bandayrel, et al. 2014. “Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults: A Meta-analysis.” JAMA 312 (9): 923–33. https://doi.org/10.1001/jama.2014.10397.

Knowler, William C., Elizabeth Barrett-Connor, Sarah E. Fowler, et al. 2002. “Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin.” New England Journal of Medicine 346 (6): 393–403. https://doi.org/10.1056/NEJMoa012512.

Latner, Janet D., and Albert J. Stunkard. 2003. “Getting Worse: The Stigmatization of Obese Children.” Obesity Research 11 (3): 452–56. https://doi.org/10.1038/oby.2003.61.

Pi-Sunyer, F. Xavier. 2009. “The Medical Risks of Obesity.” Postgraduate Medicine 121 (6): 21–33. https://doi.org/10.3810/pgm.2009.11.2074.

Puhl, Rebecca M., and Chelsea A. Heuer. 2009. “The Stigma of Obesity: A Review and Update.” Obesity 17 (5): 941–64. https://doi.org/10.1038/oby.2008.636.

Thomas, Diana M., James T. Martin, Arthur V. Lettieri, et al. 2013. “Why Do Individuals Not Lose More Weight from an Exercise Intervention at a Defined Dose? An Energy Balance Analysis.” Obesity Reviews 14 (10): 835–47. https://doi.org/10.1111/obr.12062.

Wing, Rena R., and Suzanne Phelan. 2005. “Long-Term Weight Loss Maintenance.” The American Journal of Clinical Nutrition 82 (1 Suppl): 222S–225S. https://doi.org/10.1093/ajcn/82.1.222S.

World Health Organization (WHO). 2021. “Obesity and Overweight.” WHO Fact Sheets. https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight.