Ketogenic diets in binge eating disorder with obesity

Binge eating disorder was first described in 1959 by American psychiatrist Albert Stunkard to illustrate the characteristics of a subgroup of patients with obesity and recurrent episodes of binge and uncontrolled eating; a behavior he called binge eating.

However, its existence as a separate eating disorder was ignored until the second half of the 1980s, when some studies of the prevalence of bulimia nervosa in the population found a large subgroup of individuals who did not use no compensatory behaviors after binge episodes. During the same period, it was observed that about a quarter of people who needed treatment for obesity reported recurrent episodes of binge eating but did not suffer from bulimia nervosa.

In 1994, the American Psychiatric Association (APA) included binge eating disorder (BED) as an example of an eating disorder not elsewhere specified and, in Appendix B of the Statistical and Diagnostic Manual of Mental Disorders (DSM-IV ), provided a list of diagnostic criteria for further study. Subsequent studies have confirmed that BED has distinct clinical features compared to bulimia nervosa and obesity supporting the validity and clinical utility of a diagnosis of BED. However, the disorder was not recognized by the DSM-5 as a separate diagnostic category until 2003.

Over the past 15 years, more than 2000 articles on BED have been published in international scientific journals, and today we have an in-depth knowledge of its main clinical features. However, studies have also shown the limited effect of available treatments on weight loss when BED is associated with obesity.

Recently, some authors have proposed the ketogenic diet as a potential treatment to promote both binge control and weight loss, but evidence supporting this indication is sparse. Additionally, as I will explain in this article, ketogenic diets can maintain and worsen binge eating in people with BED and obesity.

Bed and obesity

Although also present in some people of normal weight, BED is more common in obese people. The fact that binge eating episodes are not followed by regular use of compensatory behaviors and often occur in a context where there is a general tendency to overeat explains its association with obesity. Among people seeking treatment for obesity, between 1.4% and 9% meet the DSM diagnostic criteria for BED. However, episodes of binge eating have been reported in the same population, ranging from 9% to 29%.

BED and ketogenic diets

Ketogenic diets are high fat (≈60%), low carbohydrate (≈10%) and moderate protein (≈30%) diets. If individuals adhere to this diet, nutritional ketosis occurs, resulting in increased lipolysis, metabolic costs of gluconeogenesis and protein thermic effect, and reduced lipogenesis. In some people, ketogenesis also appears to cause a slight short-term decrease in appetite and hunger and increased satiety. Such effects have led some clinicians to prescribe the ketogenic diet to people with obesity and BED. This recommendation was based on the observation that people with BED often report an inability to tolerate hunger, disturbances of satiety (e.g., “they never feel full”), and food cravings, and cite these physical experiences as the most significant barrier to eating mastery. and weight loss.

The effects of the ketogenic diet in patients with binge eating episodes and obesity have only been evaluated in two case studies involving three and five patients who reported binge eating and food addiction. While describing a potentially beneficial effect of the ketogenic diet on eating behavior and short-term weight loss, both studies have significant methodological limitations. Firstly, the evaluations, having only been made in the short term, do not allow conclusions to be drawn on the long-term effects of these diets on eating behavior and weight. Next, both studies assessed the presence of binge eating with the Binge Eating Scale (BES), which has many false positives, and with the Yale Food Addiction Scale (YFAS), which assesses the controversial presence of so- saying “food addiction”. Finally, the lack of case controls precludes any conclusion about the role of ketogenic diets relative to other dietary interventions.

Dysfunctional food restriction and binge eating

People with BED and obesity very frequently report the adoption of dysfunctional dietary restriction characterized by the intermittent adoption of extreme and strict dietary rules to lose weight and change their body shape, dictating what, when and how much they are “allowed” or “not allowed” to eat. Here are examples of dietary rules characterizing a dysfunctional diet:

  • “Avoid carbs completely because they make you fat” (as recommended by ketogenic diets).
  • “Don’t eat anything after 6:00 p.m.”
  • “Eat less than 1,000 calories a day.”
  • “Eat only one meal a day.”

Dysfunctional dietary restriction is implicated in the maintenance of binge eating by the main mechanisms described in the following paragraphs (see Figure 1).

Dysfunctional dietary restriction sustains binge eating.

Source: Dalle Grave, MD

Physiological mechanisms

Hunger. Although the early stages of some dysfunctional diets (e.g. ketogenic diets) may be associated with decreased appetite, over a longer or shorter time hunger almost always takes over, and is associated with a increased concerns about food and diet. . When people succumb to hunger, they often overeat and gorge on foods they have avoided.

Craving carbohydrates. A long-term high-protein diet increases plasma levels of amino acids that compete with tryptophan for transport into the brain (eg, leucine, isoleucine, and valine), thereby decreasing tryptophan flux across the barrier blood-brain and cerebral serotonin levels mood swing and increased carbohydrate intake when introduced with diet.

Cognitive mechanisms

Control the violation effect. It is a cognitive-behavioral response to the almost inevitable breaking of the “extreme food rules” that characterize dysfunctional food restriction. Indeed, people often attribute non-compliance with food rules to a lack of will or self-worth and not to the fact that their food rules are extreme and rigid. This interpretation often determines the development of cognitive dissonance (for example, “I’m worth it if I don’t stuff myselfI’m not worth if I stuff myself”), which produces thoughts and behaviors aimed at reducing the dissonance itself (e.g., “I will never be able to control my diet; I am destined to binge my whole life, so it is better that I eat what I want and give up any attempt to control my diet”). This way, the person can continue to binge without feeling guilty.

Disinhibition. People who adopt extreme and strict dietary rules use self-control and willpower to control their eating. This rigid cognitive control makes them vulnerable to disinhibition when something else gets in the way of exercising self-control (e.g. alcohol, related mood events and changes),

False hope syndrome. Some people with BED and obesity paradoxically persist in repeated weight loss attempts with dysfunctional diets, despite previous failures. The initial weight loss often provides powerful positive reinforcement, even if it is followed by failure, as feelings of control and optimism often accompany it. Unrealistic expectations about the ease, speed, likely degree of weight loss, and potential benefits that will be achieved from weight loss tend to overwhelm knowledge from previous failures. The false hope of those on dysfunctional diets reflects the desire to believe that one can get what one wants: false hopes grow because people want to believe.

Healthy, flexible diet and binge eating disorder

A healthy and flexible diet, characterized by the adoption of healthy and flexible dietary guidelines, including the consumption of a wide variety of foods, seems to be the optimal strategy to recommend to patients suffering from BED and obesity. This recommendation is supported by a study in which rigid food control was found to be associated with higher food disinhibition scores, higher body mass index (BMI), and more frequent and severe episodes. binge eating. On the contrary, flexible food control was associated with lower levels of food disinhibition, lower BMI, less frequent and severe episodes of binge eating, lower reported energy intake, and a higher likelihood of success in coping. weight during treatment.

conclusion

Currently, we do not have empirical data supporting the usefulness and safety of ketogenic diets in the treatment of patients with obesity-associated BED. In contrast, dysfunctional diets (such as ketogenic diets that eliminate many foods) play an important role in maintaining and worsening binge eating through many physiological and cognitive mechanisms.

In conclusion, like other dysfunctional diets, ketogenic diets are “contraindicated” in the treatment of binge eating disorder and other eating disorders.

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