Restriction dieting is an utter failure and we need to stop.
Failure #1: it does not reduce weight/fat significantly
Caloric restriction fails to create significant weight loss for most people and we have known this since the 50s. Numbers vary but most people don't lose more than 10 percent of their body weight. This is because your body fights back against starvation. In technical terms, your metabolism (energy expenditure) slows to match the pace of your weight loss and it stays slower even when you gain the weight back. This is in addition to the fact that when you restrict calories, you stop moving around as much, because you have less energy to do so.
Failure #2: it does not reduce weight/fat for more than a few months
Even if you experience short-term weight loss, "one third to two thirds of dieters regain more weight than they lost on their diets." This is partly due to metabolism changes as mentioned above, partly due to hormonal changes caused by not eating, and partly due to psychological effects.
Your body is a machine that has evolved to protect you from starvation. There is a hormone called cortisol which will tell your body to retain as many energy stores as possible: it says, "store fat and don't burn it!" This hormone is activated by two things (among others I'd imagine): stress and low blood sugar. When you restrict, you activate this hormone and make your body more likely to store than to burn. It is incredibly counterproductive to restrict: even if you lose some fat at first, as this hormone builds up it will make you retain fat again.
In 1950, Keys, Brozek, Henschel, Mickelsen, and Taylor studied the effects of human starvation. Over a 3 month starvation period, participants were given the technical minimum of all necessary nutrients, so that they were not actually starving but were always hungry. The participants grew tired, irritable, and obsessed with thoughts of food.
When the refeeding stage began, they gained back all the weight they lost and even when they were back at their previous weight and eating 5 meals a day they were still obsessed with thoughts of food. Not having enough food is psychological torture and has lasting effects on your mental health, and it will change your relationship to eating.
Failure #3: it is not safe, much less healthy
Most importantly, restricting calories can literally kill you. Not eating enough to healthily sustain you weakens your heart. There aren't many studies on fat people who severely restrict calories, but the studies on thin people who restrict show how dangerous it can be.
"Cardiovascular complications are relatively common and have been reported in up to 80% of patients with anorexia, primarily in the form of bradycardia, hypotension, arrhythmias, repolarization abnormalities, cardiac failure, silent pericardial effusion, and sudden death (SD)." Yes, sudden death. It is also dangerous even for young people.
People engage in these diets because they believe the myth that eating too much is what causes you to be fat. This was disproved in the 70s, when Sims, Danforth, Horton, Bray, Glennon, and Salans experimented with overfeeding: most participants had to double their caloric intake in order to gain weight and not all of them were able to reach their goals (20 to 30 pounds). One person was eating over 10,000 calories every day and still could not reach that goal.
When this study was over, most people lost the weight they had gained, with the exception of people who had fat relatives. Why? because how well your body holds on to fat is genetically determined. So far we have discovered at least 8 genes that predict fatness. Twin studies show that genetics have more impact on weight than home environment, and "overall, the heritability of obesity is estimated at 40% to 70%." We can expect this number to rise as genetics research advances.
Restriction dieting (including that trendy euphemism "intermittent fasting") hurts you and does not result in permanent weight loss. It is a catastrophic failure and then some.
1.) Redman LM, Heilbronn LK, Martin CK, et al. Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss. PLoS ONE. 2009;4(2):1-9. doi:10.1371/journal.pone.0004377.
2.) 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. American Psychologist. 2007;62(3):220-233.
3.) Tomiyama AJ, Mann T, Vinas D, Hunger JM, Dejager J, Taylor SE. Low calorie dieting increases cortisol. Psychosom Med. 2010;72(4):357–364. doi:10.1097/PSY.0b013e3181d9523c
4) Oflaz S, Yucel B, Oz F, et al. Assessment of myocardial damage by cardiac MRI in patients with anorexia nervosa. International Journal of Eating Disorders. 2013;46(8):862-866. doi:10.1002/eat.22170
5.) Spaulding-Barclay MA, Stern J, Mehler PS. Cardiac changes in anorexia nervosa. Cardiology in the Young. 2016;26(4):623-628. doi:10.1017/S104795111500267X.
6.) Choquet H, Meyre D. Genetics of Obesity: What have we Learned?. Curr Genomics. 2011;12(3):169–179. doi:10.2174/138920211795677895
7.) McPherson R. Genetic contributors to obesity. Can J Cardiol. 2007;23 Suppl A(Suppl A):23A–27A. doi:10.1016/s0828-282x(07)71002-4
Not convinced yet? Try these two articles brimming with evidence:
The Weight of the Evidence: It’s time to stop telling fat people to become thin by Harriet Brown
Everything You Know About Obesity Is Wrong by Michael Hobbes
Edited to add more articles:
Dieting doesn't work. Rather than counting calories and stigmatising fat, we need to take on the food and weight-loss industries. -Susie Orbach