March 2020 Issue

Exercise & Eating Disorders
By Carrie Dennett, MPH, RDN, CD
Today’s Dietitian
Vol. 22, No. 3, P. 36

Cultivating a Healthful Approach to an Activity Regimen as Part of Treatment

The health benefits of physical activity are clear, but when someone is being treated for an eating disorder—especially anorexia nervosa (AN)—many health care providers suddenly view exercise as unhealthful. The idea that exercise interferes with eating disorder recovery has been solidly entrenched in the eating disorder treatment world, yet that idea is starting to be questioned—although not without some controversy.

Dysfunctional exercise—typically described as exercise addiction, exercise dependence, or compulsive exercise—includes maintaining rigid exercise regimens, exercising despite physical injuries, feeling anxious if unable to exercise, prioritizing exercise before other important activities, or rigidly imposing exercise before or after an eating binge.1 It’s listed as one of the compensatory (or “purging”) symptoms of bulimia nervosa (BN) in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition.2    

Because dysfunctional exercise frequently is a symptom of eating disorders—one that often predates the full onset of the eating disorder, contributes to relapse or persistence, and is one of the last symptoms to resolve—the common practice has been to intervene by prescribing exercise abstinence.3,4

“We’re still hung up on the idea of calories in, calories out, that exercise burns calories, and people with anorexia don’t have calories to burn,” says Brian Cook, PhD, Monterey, California–based vice president of movement, research, and outcomes for Alsana Eating Disorder Treatment & Eating Recovery Centers. He says one influencing factor is the number of 1970s case studies of emaciated girls with AN who had been engaging in hyperactivity.5 “This gives us the idea that exercise is the problem,” he says. In fact, he’s heard people in the eating disorder field say that exercise causes eating disorders, but if that were true, “we’d all have an eating disorder.”

Cook says the belief that if eating disorder clients are allowed to exercise, they’ll just go off the “deep end” isn’t what’s actually happening in the structured exercise programs used in research and clinical practice.

A 2018 study in the Journal of Eating Disorders found that in a population of women undergoing treatment for BN or binge eating disorder, a 16-week intervention that combined physical activity and dietary therapy was as effective as cognitive behavioral therapy (CBT) for reducing compulsive exercise.2 The authors noted that only 54% of the BN patients didn’t meet minimum recommendations for moderate to vigorous physical activity at baseline, yet some of those patients also scored above the cutoff point on a self-report assessment of compulsive exercise. This suggests that while many patients may have dysfunctional attitudes towards exercise, these attitudes don’t always translate to action.

This is consistent with results of a 2006 study that found that, among women with eating disorders, more than 45% of those with the purging (no binging) subtype of anorexia were sedentary or had “normal” exercise patterns. That number jumps to almost 60% for women with the restrictive subtype and is even higher among women with bulimia or the binging/purging subtype of anorexia.4 Cook emphasizes that, while eating disorders have been around since the beginning of human history, the science of eating disorders is fairly young. “It’s only in the last 45 years or so that we have a formal study of eating disorders.” Surprisingly, in some ways, the research on exercise also is relatively young. “It really wasn’t until recently that we had an understanding of exercise and what it does physiologically as well as psychologically with the mind-body connection,” he says. “That’s changing pretty rapidly.”

What Does Therapeutic Exercise Look Like?
Indeed, more evidence is demonstrating that exercise is both safe and beneficial for eating disorder patients. This means the question is more nuanced than whether to recommend exercise. It’s how to make sure that exercise is supporting health rather than supporting the eating disorder.

A 2016 review coauthored by Cook looked at research from different fields on the role of exercise in eating disorder treatment and suggested guidelines for using exercise therapeutically.6 They include involving a multidisciplinary team of experts in exercise, mental health, medicine, physical therapy, and nutrition—specifically, a dietitian with expertise in eating disorder refeeding and weight restoration. This may make therapeutic exercise more practical in hospital-based or residential treatment.

Tammy Beasley, RDN, CEDRD, vice present of clinical nutrition services for Alsana, says that even with patients who had been severely restricting, once blood pressure, blood glucose, and other biometrics are stable, it’s unnecessary to wait for weight restoration before starting activity. “I think what has happened in our field is progressive movement, starting with no movement then yoga then maybe walking by the end,” Beasley says. “We’re trying to move away from that, instead including movement as a part of life.” She says that using metabolic equivalents, or METs, dietitians easily can calculate how many calories, say, a 15-minute walk will use. “As long as that fuel has been consumed in their plan for the day, they know that movement will be covered.”

Exercise does need to be tailored to each patient, including creating a graded exercise program that begins with short bursts of low-intensity exercise. Cook points out that exercise doesn’t have to be intense to have benefits. A 2019 meta-analysis found no difference in the health benefits from accumulated low-intensity vs continuous exercise.7 Other research suggests that people are more likely to stick with low-intensity activity because it’s more enjoyable.8

The patient-provider team also has to agree how exercise will be used—including rules, goals, outcomes, and expectations—with permission to exercise contingent on treatment compliance (positive reinforcement). However, Beasley says revoking permission is best framed as a natural consequence rather than a punishment. For example, saying “You’re not going to be able to join the group walk today because your body doesn’t have the fuel it needs for energy and repair,” instead of “You can’t go on the walk today because you didn’t follow your meal plan.” In other words, not making exercise the carrot at the end of the stick.

Debriefing sessions also are important to discuss the sensations, thoughts, and emotions experienced during exercise. “Our biggest goal is not just to address the behavior, but what goes in and what comes out. This includes processing before, during, and after,” Beasley says. “Including exercise in treatment allows them to practice in a safe space; it allows them to deal with the stuff that comes up around exercise with support.” For example, if a patient feels that a 15-minute walk on the beach wasn’t enough, and that they needed to walk for another hour, the provider could explore why 15 minutes “wasn’t enough,” ask them whether they enjoyed it, and explain why they don’t currently have the energy to exercise for longer durations.

Influence of Exercise on Weight
Many clinicians assume that eating disorder clients will lose weight if they exercise, but Cook says that’s generally not true—even in underweight patients—when exercise is used in a structured, therapeutic way and accompanied by adequate nutrition. That’s a very different scenario from unsupervised, compensatory exercise performed during times of nutritional deficiency.9

“There is a huge misconception that exercise influences weight loss, but exercise is not an efficient way of purging calories,” Cook says, with the caveat that patients have to also be eating for weight gain to happen. He says the body prefers to use fuel from food for energy rather than dipping into our body’s fat or protein stores. “Exercise triggers the body to use fuel in a way that’s more productive.”

Cook says it’s easy to confuse compensatory exercise—exercise done to compensate for eating—with starvation-induced hyperactivity, a phenomenon also known as activity-based anorexia, which is largely based on rat studies. In these studies, food-restricted rats engage in excessive activity when given free access to a running wheel, leading to a sharp drop in weight, self-starvation, and eventually death.10 However, that’s not how things work in humans. “Generally, when we ask our body to use energy, our body likes to consume energy,” he says.

A 2018 study looked at 244 patients admitted to an inpatient eating disorder treatment unit in Norway between 2003 and 2017. The unit used a multidisciplinary team and individualized exercise plans based on each patient’s symptoms and needs. Researchers reported no cases in which exercise impaired patients’ recovery process or prevented weight gain.11 A 2013 meta-analysis found no significant differences in weight outcomes between groups that included supervised exercise training and groups that followed usual treatment, while the studies in the analysis that only included an exercise group found improvements in weight and body fat.12

“The biggest concern we see in clients is when food becomes compensatory—when they say, ‘I don’t need to eat anything because I’m not exercising,’” Beasley says. “A lot of the work we do is to help the client understand that their body is incredibly active all the time, even when they’re not moving, so they’re able to embrace that they need fuel at all times.”

She says this includes avoiding statements such as, “You’re able to exercise more now, so you need an extra snack,” which would feed into the compensatory mindset. “If a client is going to go for a walk on the beach, we have to ensure that we’ve fueled their body for that 15- to 20-minute walk so they have immediate fuel for that moment, but it’s an ongoing consistent fueling.”

Perfectionism vs Excellence
While striking a balance between physical activity and nutritional intake appears most beneficial, exercise dependence and eating disorders each reduce health-related quality of life, and together those effects are amplified, possibly because of pathological motivations to exercise.13 Of the anorexia subtypes, the purging subtype is most associated with excessive exercise, especially in younger patients and those with higher degrees of anxiety, depression, obsession, and perfectionism.4 Perfectionism is linked with both eating disorders and dysfunctional exercise, and exercise can straddle a thin line between perfectionism and excellence.

“If you are striving toward excellence, you are striving to be the best you can be,” Cook says. This includes accepting your limitations. “Perfectionism is more like, ‘If some is good, more is better.’” Perfectionism is disconnected from reality and is externally focused, while excellence is more internally focused. Cook says that when excellence is the goal, exercise can become a way of achieving self-realization or even self-actualization. He says this is counter to workout programs that prescribe a certain workout on a certain day or squeeze 90 minutes of exercise into an intense 15-minute session (something that many people—with or without eating disorders—participate in). “How is that respecting the internal state that you are at?” he says.

Mental Health Benefits
Along with perfectionism, dysfunctional exercisers are more likely to show high levels of psychological distress and struggle with depression, anxiety, or obsessive-compulsive disorder.3 A 2016 study found that AN patients who had a greater discrepancy between their actual weight and ideal selves—which is related to overestimating body size—was associated with higher levels of driven exercise.14

While weight restoration in AN is clearly important, it’s not the only benchmark of recovery. Eating disorders have many psychological underpinnings, and appropriate physical activity can improve mood, body image, self-esteem, and self-efficacy. It also can help patients connect with nature—and humans.

Beasley likes to encourage “movement with a purpose” by including movement as a part of other life activities. She often does scavenger hunts with patients as a way to laugh and have fun together while simply moving. Dietitians on her staff may walk with patients on the nearby trails as part of their session, stopping to sit and rest after an appropriate duration.

“For too many years, we’ve had this dualistic idea where people ignore the mind-body pathway,” Cook says. In other words, clinicians have believed that anything above the neck is all made up. He says that any psychological state has a physiological underpinning, and that many metabolites that benefit the brain are part of the neurobiological cascade that comes from movement. “Exercise is the straw that stirs the drink.”

A 2013 review found that yoga and aerobic exercise decreased the number of binges in patients with binge eating disorder and that combining aerobic exercise with CBT was more effective at reducing symptoms of depression than CBT alone.15 Aerobic exercise, yoga, massage, and basic body awareness therapy significantly lowered scores of eating pathology and depressive symptoms in both AN and BN patients.16

Cook says exercise requires a holistic view that includes patience, not a “beat yesterday” mentality to achieve the best mind-body benefits. He says people are on board with the idea that exercise can help with depression and anxiety—but that generally requires a sustained program of exercise for about four to six months, along with rest days and nutrition. “The point of the journey is not to arrive; it’s to trust the process.”

Physical Health Benefits
The established benefits of physical activity for muscle and bone health in any population may be even more important for individuals who have had their muscle and bone compromised because of restrictive eating disorders.

Decreased bone mineral density is a common complication of AN, and one that can persist after recovery. Eating disorder¬–related bone loss is multifactorial, including loss of estrogen, high cortisol levels, calcium and vitamin D deficiencies, and loss of lean body mass, which in turn reduces the bone-building effects of muscle contractions.

Beasley says eating disorder–related bone loss never can be fully reversed but that exercise offers more hope for increasing bone mineral density than estrogen replacement or nutrition, at least initially.17 During the earlier stages of renourishment, even though patients are getting more food and more sources of calcium, their gut is still healing, which limits their ability to absorb the nutrients important for bone health. “It’s an uphill battle with the food and absorption, so I feel like, how can we not add movement? It’s almost the only way that we have to help patients at this point. Our clients’ bones can’t wait another day.”

A small 2014 study randomized 36 adolescent females who were undergoing treatment for restrictive type AN to either a supervised eight-week high-intensity resistance training program or to a no-exercise control group. The three-days-per-week exercise protocol included three sets of eight to 10 repetitions of exercises that work all the major muscle groups, with warm up and cool down periods. The exercise group improved both strength and agility compared with the control group, while neither group experienced decreases in weight or BMI. Specifically, upper body strength increased by an average of 37% to 41% and lower body strength increased by an average of 52%.18 Another 2014 systematic review of eight small studies (213 patients total, aged 16 to 36) found that supervised aerobic and resistance training significantly increased muscle strength, BMI, and body fat percentage in AN patients.16

Food for Thought
“There’s a lot of fear about including exercise in treatment, but movement is life,” Beasley says.

In a 2017 article on the ethics of exercise in eating disorders, Cook suggests that “restricting all forms of exercise is an ethical issue because doing so eliminates autonomy, respect, empathy, and dignity for individuals with [eating disorders] by preventing them from partaking in socially acceptable healthy lifestyle behaviors and taking control of their recovery.”9

— Carrie Dennett, MPH, RDN, CD, is the nutrition columnist for The Seattle Times, owner of Nutrition By Carrie, and author of Healthy for Your Life: A Holistic Guide to Optimal Wellness.


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