This is a short discussion that I recently posted as part of one of my classes for grad school, and it includes a lot of research to support the fact that low calorie diets don't work!
Many still believe that existing on an extremely low calorie diet will ultimately lead to sustained, long-term weight loss, but I do not believe that a diet excessively low in calories can offer a long-term approach to achieving and maintaining weight loss. In my opinion, for individuals who are attempting to lose weight, not only does this ‘deprivation’ method encourage the body to create a low metabolic set-point (which leads to a slower metabolic rate and plateau of weight loss), but it also encourages individuals to consume low-calorie, low-benefit foods, which are void of the necessary components of a healthy diet (vitamins, minerals, and natural compounds). I chose this topic because I have personally followed many calorie-restrictive diets, and these diets have only made my quality of life worse in the long run. My goal is to teach others that a better approach is to gradually increase caloric intake in a beneficial macro proportion (promoting whole foods), which encourages the body’s natural metabolic adaptations, ultimately leading to an increase in the body’s basal metabolic rate (BMR) (Diaz 1992), an increase in fat-free body mass, and sustained fat loss (or maintenance) over time.
In a review of 33 trials evaluating diet, exercise, or diet and exercise, it was concluded that in individuals that lost weight, this weight loss was not sustained for greater than 1 year. (Curioni, et. al 2005). Low calorie diets do not result in sustained (>1yr) weight loss, and the probability of an obese person obtaining a normal body weight, or maintaining a normal body weight after significant weight loss are very low (Fildes, et. al 2015). There are several factors that contribute to this fact, but one of the factors is called ‘Adaptive Thermogenesis’, which causes an individual’s body to begin burning less calories after they have lost weight (Johansson, et. al 2014). This creates a constant battle of attempting to build up a calorie deficit between intake and expenditure, but upon weight loss, the body innately wants to reach equilibrium. In addition, there is a psychological component to the inability of individuals to attain and sustain weight loss. Oftentimes, the emphasis is put on what people can not eat, rather than what they can eat, and this negative focus does not appear to result in greater weight loss (Spake 2005).
On the other hand, when individuals are presented with an increase in overall caloric intake, the potential for an increase in basal metabolic rate (BMR) as a result of the additional calories can actually result in an overall increase in fat-free mass (a.k.a “muscle”) (Diaz et. al 1992). It has been shown that restrained eaters are more likely to show patterns of overeating in various settings (Ogden 1995), and because there are multiple reasons (not all related to actual hunger) why people eat (Gast & Hawks 2000), it is important to take into consideration these non-hunger as well. In addition, by offering individuals the freedom to eat more intuitively without excessively restricting calories and creating a feeling of deprivation, habits such as binge eating can occur less frequently, or not at all (Gas & Hawks 2000).
Following a low calorie diet can have an extreme emotional impact to those who follow such a diet for a sustained amount of time, and repeated-dieting can even lead to violent behavior (Shiraishi et. al 2014). It has been shown that periods of caloric restriction can lead to greater body dissatisfaction, depression, loss of control, and preoccupation with food (Ogden 1995). Also, for people who have lost a substantial amount of weight, after continuously reducing calories over time, they can potentially reach a point where they are consuming less calories per day than their body can optimally perform on, based upon recommendations from the USDA (2002). Individuals who have been following a substantially low calorie diet for a long period of time often develop fears surrounding food, and dieting behavior can actually increase the risk factors for developing long-term disordered eating patterns (Roehrig, et. al 2008).
In the long-term, it is much more effective for an individual to learn how to properly balance their eating patterns in an intuitive, non-calorie-restrictive format. This method not only supports the body’s overall thermogenic processes, but it also better supports an individual’s mental wellbeing.
Curioni, C. C., Louren & ço, P. M., & Lourenço, P. M. (2005). Long-term weight loss after diet and exercise: a systematic review. International Journal Of Obesity, 29(10), 1168-1174. doi:10.1038/sj.ijo.0803015
Diaz, E. O., Prentice, A. M., Goldberg, G. R., Murgatroyd, P. R., & Coward, W. A. (1992). Metabolic response to experimental overfeeding in lean and overweight healthy volunteers. The American Journal Of Clinical Nutrition, 56(4), 641-655.
Fildes, A., Charlton, J., Rudisill, C., Littlejohns, P., Prevost, A. T., & Gulliford, M. C. (2015). Probability of an Obese Person Attaining Normal Body Weight: Cohort Study Using Electronic Health Records. American Journal Of Public Health, 105(9), e54-e59. doi:10.2105/AJPH.2015.302773
Gast, J. A., & Hawks, S. R. (2000). Examining Intuitive Eating as a Weight Loss Program. Healthy Weight Journal, 14(3), 42.
Johansson, K., Neovius, M., & Hemmingsson, E. (2014). Effects of anti-obesity drugs, diet, and exercise on weight-loss maintenance after a very-low-calorie diet or low-calorie diet: a systematic review and meta-analysis of randomized controlled trials. American Journal Of Clinical Nutrition, 99(1), 14-23. doi:10.3945/ajcn.113.070052
Ogden, J. (1995). Cognitive and Motivational Consequences of Dieting. European Eating Disorders Review, 3(4), 228-241.
Roehrig, M., Thompson, J., & Cafri, G. (2008). Effects of dieting-related messages on psychological and weight control variables. International Journal Of Eating Disorders, 41(2), 164-173 10p.
Shiraishi, N., Nishida, A., Shimodera, S., Sasaki, T., Oshima, N., Watanabe, N., & ... Okazaki, Y. (2014). Relationship between Violent Behavior and Repeated Weight-Loss Dieting among Female Adolescents in Japan. Plos ONE, 9(9), 1-7. doi:10.1371/journal.pone.0107744
Spake, A. (2005). EAT MORE WEIGH LESS. (cover story). U.S. News & World Report, 138(8), 50-58.
U.S. Department of Agriculture (2002). Estimated calorie needs per day by age, gender, and physical activity level. Retrieved from http://www.cnpp.usda.gov/sites/default/files/usda_food_patterns/EstimatedCalorieNeedsPerDayTable.pdf
Wolpert, S. (2007). Dieting does not work, UCLA researchers report. UCLA Newsroom; Science + Technology. Retrieved from http://newsroom.ucla.edu/releases/Dieting-Does-Not-Work-UCLA-Researchers-7832