Why Should You Stop Dieting? Because Diets Don't Work — Experts Explain 7 Reasons Why

Registered dietitian Brenna O'Malley, creator of the health blog The Wellful, said that we have an abundance of research showing us that diets "work" in the first few months, and it's also what many experience when starting a different diet plan. "That change in weight isn't what's being disputed," she said. "It's the sustainability of that loss, and the risk and side effects that come with it." Sure, the weight may come off if you eat 1,000 calorie a day, but O'Malley asked, at what cost to your mental and physical health will such restrictive dieting cause? You can't maintain a diet like that without causing harm.

Many diets and lifestyle plans aren't sustainable, one reason being that the restriction in calories leads to participants feeling out of control around food, because the body's physiological response to restricting is binge eating.

The diet may also be difficult to maintain if it doesn't fit in with their social or work lifestyle, if it limits their social engagements, or prevents them from being flexible, traveling, or having spontaneous plans. For example, if you're following a strict keto diet, you may be worried about not being able to eat or being tempted to "break your diet" if you go to a party or on a trip.

Another reason diets aren't sustainable is because they're not individualized to that person. O'Malley said, "We all have different food preferences, needs, lifestyles, health histories, and relationships with food, so it makes sense that there isn't one way of eating that would work for all of us."

In 2007, Traci Mann, who has a PhD in psychology, conducted a review of every randomized controlled trial of diets and included a follow-up of at least two years. She and her team discovered that one-third to two-thirds of dieters regained more weight than they lost on their diets — more weight! Lauren Cadillac, RD, CPT, a certified intuitive eating counselor, explained that this proves that dieting is a predictor of weight gain, which means if you diet, you could end up weighing more than you did before you started.

In 2013, Mann updated her review with studies she missed as well as newer studies and the results were the same. While dieters in the studies had lost weight in the first nine to 12 months, and over the next two to five years, they had gained back all but an average of 2.1 of those pounds. Participants in the control groups who did not diet also gained weight during those same years, but an average of just 1.2 pounds.

One study showed that half the dieters weighed over 11 pounds more than their starting weight five years after starting the diet. The dieters made little progress in terms of their weight, and the non-dieters weights weren't greatly affected by their lack of dieting. Mann said in the study, "In sum, it appears that weight regain is the typical long-term response to dieting, rather than the exception."

From the 2013 Australian Research Council's clinical guidelines for the management of obesity, they discovered that after ending dieting, people end up gaining back most of the weight lost within two years. Within five years, most people gained back all the weight. O'Malley explained that this research proves that regardless of participants being able to lose weight initially, it wasn't in a way that the participants could maintain.

O'Malley shared a great quote from Evelyn Tribole, registered dietitian and co-author of Intuitive Eating, "The weight loss industry is the only industry where a customer buys a product that doesn't work and the manufacturer blames the customer."

If a person isn't consuming adequate calories or they're cutting out certain food groups, they may be missing out on essential vitamins, minerals, and nutrients their body needs to function normally. Cadillac said this can cause a weakened immune system, loss of muscle, cardiovascular issues such as high blood pressure, cardiovascular disease or stroke, metabolic syndrome, and increased mortality risk. Yo-yo dieting in women, where you cycle between losing and gaining weight, can also increase heart disease risk.

Some will argue that being at a higher weight is unhealthy, but O'Malley said that research shows those at higher weights can have similar or better health markers than those at lower weights. This type of research is what helps us untangle the assumption that our weight equals our health, which is often the basis for the push to lose weight. O'Malley said, "Recognizing this research and having more of us know this helps us to be more critical of diet culture messages around the need to lose weight to be healthy, because we know that's not always the case. And combined with weight cycling research, we can see that even the pursuit of weight loss over time with different diets can actually result in worsened mental and physical health markers."

It was proven in The Biggest Loser studies O'Malley brought up when we saw contestants having extreme changes in weight, and also saw significant changes to their metabolisms — they slowed, meaning their basal metabolic rate (BMR) was much lower than it had been before.

Extreme calorie restriction through diet and exercise slows down your metabolism, so not only will you eventually stop losing weight, but as soon as you eat a little more or exercise a little less, you'll gain weight.

Your body is smart. It's wants you to survive. It doesn't care that you want a six-pack. If you don't feed it adequate calories to sustain your body's essential functions, your metabolism will slow down so you won't lose weight.

Leptin is the hormone that sends the "I'm full" message to your body, so you stop eating. Researchers from The Biggest Loser study also found that dramatic weight loss caused a decrease in leptin levels, which lead to increased cravings and hunger. It's impossible to fight these strong physical urges, making it more difficult to continue with a low-calorie diet.

All the experts agreed that dieting can lead to obsessively counting calories and macros, constantly thinking about food, increased cravings and hunger, bingeing in response to restricting, as well as eating disorders like anorexia and bulimia. Having your brain consumed by your weight, what you eat, and what you look like will affect your relationships, your school or work, and could even be fatal.

One of the best examples of the effects of dieting is the Minnesota Starvation Experiment in 1944, O'Malley shared. Thirty six men were selected from a couple hundred volunteers. The goal was to help researchers and relief workers learn how to help people recover from starvation during WWII by studying the psychological and physiological effects of starvation.

The important takeaways to highlight from this study are that after the 'semi-starvation' period of six months where the men ate 1,570 calories per day (3,200 calories a day was normal), the participants reported experiencing depression, apathy, decreased sex drive, decreased strength and stamina, as well as reduced body temperature and heart rate.

They also displayed symptoms of obsession with food - dreaming and fantasizing about food, reading about food, reading cookbooks, talking about food, and savoring their meals with ritual-style eating that prolonged mealtime. Following the study, even after the men were allowed to resume "normal" eating, the participants would binge on large quantities of food, and for some men, this continued later than eight months after the study. "This demonstrates the long-term effects of restriction on the body," O'Malley said.

"This is very similar to what we see in behavior of not only those who struggle with eating disorders but also very normalized behaviors from those who diet or restrict eating in some way," added O'Malley.

Cadillac added that dieting can also lead to social anxiety, social withdrawal, and feelings of failure. As if that wasn't bad enough, Previte said feeling bad about your weight and constantly dieting can also cause anxiety, poor self-esteem, as well as suicidal thoughts.

O'Malley noted that the men's calorie allowance was definitely low, but not as low as you might think for a "starvation study." She said that "many calorie-tracking apps and meal plans are giving similar numbers and that more often than not, those numbers are underestimating your needs." So while your calories may not be so low that you're starving, they may be so low that they're causing these emotional issues.