In my last post, I talked about the diet-binge cycle that results from trying to restrict certain foods or overall calories. I didn’t go into detail about the physical and psychological effects of dieting, so that’s what we’ll discuss today. And there are a lot of negative effects of dieting, despite the widely-accepted belief that dieting is good for your health.
Brain and Hormone Changes
Many dieters restrict carbohydrates, which is a primary source for glucose, but our brains needs glucose to function properly. “If carbs are strictly reduced, the brain will be cut off from its main energy source, which can drastically alter brain functioning,” says Cheryl Mussatto, RD (registered dietitian). “One such change can occur with serotonin, a chemical produced by the brain. Serotonin regulates our sleep cycle, mood and appetite, all of which will be noticeably altered along with experiencing brain fog.”
Also, as Jillian Greaves, RD explains, “If you’re overly restricting carbohydrates, this is a form of stress on the body that can disrupt normal endocrine function.” The endocrine system, responsible for your hormones, is related to many other systems in the body. “This disruption may contribute to cravings, an irregular or stopped menstrual cycle, hypoglycemia, mood swings, anxiety, chronic fatigue, suppressed immune function and thyroid disturbances.” Some studies show that low-calorie diets raise the stress hormone, cortisol, which can have some serious negative health effects over time.
Additionally, our brain is made up of 80% fat and also needs dietary fats to function properly. If you don’t eat enough fat, you may miss out on some of the brain-boosting benefits of dietary fats including better memory, lower risk of dementia and Alzheimer’s, and better focus and concentration. Medical studies indicate that people on diets have slower reaction times and less ability to concentrate than people not on a diet.
Dieting causes your metabolism to slow down to conserve energy and send it right back into building up fat stores. Also, a 2011 study shows that changes to appetite mediators—so-called “hunger hormones”—promote weight regain after diet-induced weight loss. These compensatory mechanisms driving weight regain last for at least one year and could be long-term or even permanent.
Some research connects restrictive dieting with poor sleep quality. In one study, even a short period of dieting (just four weeks) resulted in a significant decrease in the amount of time women spent asleep and a greater difficulty falling asleep. Sleep is an important part of health and a lack of sleep can result in inflammation, an increased risk for diseases, and other concerning side effects.
Many important vitamins like vitamins A, D, E and K, are fat-soluble, and your body needs fat to properly absorb those vitamins. Without enough fats, the vitamins you eat can pass through your system unabsorbed and can result in nutrient deficiencies. Also, restricting entire food groups can cut out main sources of important nutrients.
Weight Cycling (aka Yo-Yo Dieting)
Weight cycling describes the pattern of repeatedly losing and regaining weight, often with increased overall weight in the long-term. “Long-term diet research (two years or longer) suggests that most people regain all the weight lost during a diet, whether they stick to the diet or not,” Julie Dillon, RD says. “In fact, many regain more weight than was lost in the first place.” One 2016 study found that repeatedly going through these starvation cycles prompts your body to store more fat, which is likely a survival response against starvation. Also, dieting slows down your metabolism, as previously discussed. “If you follow people over the long term, dieters are more likely than equivalent non-dieters to end up gaining weight over the next 2 to 15 years after the diet,” says Sandra Aamodt, PhD, author of Why Diets Make Us Fat.
Weight cycling is linked with increased insulin resistance, a condition which can develop into type 2 diabetes (T2D). In other words, maybe yo-yo dieting is a more likely cause of T2D than weight itself! Weight cycling also causes other health complications such as higher blood sugar, blood pressure, cholesterol, risk of heart disease, and inflammation. In many cases, acute inflammation is a necessary and helpful human function that can promote healing in response to infection or injury. However, sometimes inflammation is chronic, which can make you feel drained or foggy and harms health, Dillon explains. “Short-term research suggests many diets lower inflammation, but research looking six months out or more shows that inflammatory markers increase.”
Overeating & Bingeing
Weight is actually regulated by our bodies, and each of our bodies prefers to be within a certain weight range, called a set point. “Your brain will defend this amount just like it defends your body temperature,” explains says Stephan Guyenet, PhD, author of The Hungry Brain. As you lose weight, the amount of leptin in your bloodstream drops and sends a signal to your brain to help you fight to bring that fat back (remember those hunger hormones I mentioned earlier?). This is at the heart of why diets don’t work, says Aamodt (author of Why Diets Make Us Fat). “Whenever your weight changes too much, your brain will intervene to push it back to what it thinks is the correct weight for you.” This push-back from your brain is what Guyenet and others call a classic starvation response: your brain responds by upping hunger and cravings.
“In lab experiments, when scientists want to induce rodents to binge eat, the most reliable method for doing it is to reduce food intake until they’re at a lower weight and then expose them to super tasty food, like Cocoa Puffs or Oreos,” Aamodt explains. She adds that in human research, some studies that look at the brain show that this type of junk food activates reward centers even more fiercely in those who have lost weight. And, she says, animal research may suggest that repeated dieting makes the brain more vulnerable to binging behavior even after the diet is done.
Your body prefers to use carbs for a number of basic brain functions, so eating too few of them can cause your brain to fight back. “Cutting out carbs through any low-carb diet (including paleo and keto) can set a person up for binge eating in part because when we don’t eat enough carbohydrates, our body releases a brain chemical called neuropeptide Y,” says Julie Dillon, RD. “This chemical’s job is to tell our body to eat carbs — and eat them now.” When a person’s brain is flooded with this chemical, it can result in an animal-like instinct to go crazy on carbs — attack a plate of brownies or eat an entire pizza, for example. “It can feel like every cell in your body is demanding carbs, which can lead you to feel that you lack willpower,” Dillon explains. “But it has nothing to do with discipline. Rather, this neurochemical is trying to save your body from experiencing fainting, dizziness or worse!”
Body Image & Self-Esteem Issues
You might think that going on a diet would make you feel better about your body, but research shows quite the opposite. A study of college students showed that for men and women, dieting (even diets described as “normal” in severity) resulted in an increased concern with weight and a lower self-esteem. Another larger study showed that both men and women who reported dieting behaviors were less likely to have a positive body image. And of course, I think we are all familiar with the feelings of shame, failure, and poor self-image that happens whenever we “fail” at a diet.
Preoccupation with Food & Eating Disorders
The Minnesota Starvation Experiment, conducted in the 1940s, revealed groundbreaking information about how calorie deprivation affects the human brain. “It demonstrated that a lower calorie intake provokes the mind to overly think about food,” explains Dillon. Even years after the study had ended and participants again began eating a higher number of calories, participants who had been limited to diets of 1,500 calories per day found they felt fixated on food. Some participants even changed their careers, eventually becoming chefs. “Dieting provokes the brain to dream about food and consume thoughts. We believe this is a necessary evolutionary response to not eating enough,” Dillon says. And as we previously discussed, the response to deprivation is often bingeing, which can lead to eating disorders like binge eating disorder (BED) and bulimia nervosa.
But problems can arise even if the body is getting enough calories. Some dieters aren’t focused on consuming fewer calories as much as they are concerned about avoiding certain foods, sometimes entire food groups. Though these types of dieters might start out with good intentions of eating healthy, too often the diet rules progress into rigid thinking about food and disordered eating… sometimes even an eating disorder that has been termed “orthorexia” (orthorexia is characterized by an obsession with “healthy” eating).
“Research suggests going on any restricted diet places a person at a higher risk for experiencing depression,” Dillon says. Numerous studies also link chronic dieting with increased stress and anxiety. Neither is surprising since, as we learned earlier, dieting affects serotonin functioning. Of the approximately 40 million brain cells we have, most are influenced either directly or indirectly by serotonin. This includes brain cells related to mood, sexual desire and function, appetite, sleep, memory and learning, temperature regulation, and even some social behavior.
- Some people who diet, especially those on keto, might experience bad breath and even vaginal odor (a side effect referred to as “keto crotch”)
- Dizziness, light-headedness, and lethargy/decreased energy
- Decreased sex drive
- Not eating enough carbs, a primary source of fiber, can lead to constipation, bloating and other digestive issues
- Social isolation due to not being able to participate in social activities involving food
- Decreased hunger and fullness cues
If Not Dieting, Then What?
Like me, Aamodt (author of Why Diets Make Us Fat) and other anti-diet professionals advocates for a style of eating called intuitive eating. It’s a non-dieting approach that allows you to listen to your body and nourish it with what it wants (sometimes kale, sometimes a brownie) in the amounts it wants (more or less depending on your hunger). It might sound too good to be true, and while it’s not, there is a catch. Intuitive eating is not just another diet disguised as “wellness”; the goal is not weight loss and that can be a barrier for some who are intent on losing weight.
As I said in my last post, I totally understand that giving up on intentional weight loss is difficult for so many reasons. It can be done though! If you’re interested in learning how to ditch dieting and making peace with your body and food, check out my resources page or please contact me.
I’m Cherie Miller, MS, LPC, founder of Food Freedom Therapy™. I offer counseling for chronic dieting as well eating disorder therapy for Anorexia, Bulimia, Binge Eating Disorder, Orthorexia, ARFID, and other eating disorder issues. Contact me here or follow me on Instagram or Facebook.