Psychiatric Disorders

Symptom impact and safety of ketogenic therapy in adults with anorexia nervosa: a feasibility trial

Despite weight restoration, many people with anorexia nervosa (AN) continue to experience persistent eating disorder symptoms and high rates of relapse. Researchers investigated whether a ketogenic dietary therapy (KT) could be safely implemented in adults with AN and whether it might improve eating disorder psychopathology and related psychological symptoms.

The study enrolled 22 women aged 18–45 years with AN who were either weight-restored or mildly underweight (BMI >17.5  kg/m²). Participants followed a ketogenic diet designed to provide approximately 70% of calories from fat, 20% from protein, and 10% from carbohydrate for 14 weeks. The intervention was intended to maintain body weight rather than induce weight loss. Nutritional ketosis was monitored through blood β-hydroxybutyrate (BHB) measurements taken daily during the first 14 days and weekly thereafter, with a target BHB range of 0.5–3.0 mmol/L. Participants were monitored weekly for body weight, ketone levels, symptoms, and adverse events.

Results / Key Findings

Feasibility and retention:

• Eighteen of 22 participants (82%) completed the 14-week intervention.

Body weight and safety:

• BMI remained stable throughout the study, with no participant dropping below the minimum BMI threshold of 17.5 kg/m².
• Average BMI change was not statistically significant.
• No serious adverse events occurred.
• Reported side effects were generally mild and transient, including nausea, constipation, and dehydration.

Eating disorder symptoms: 

• Eating Disorder Examination Questionnaire (EDE-Q) Global scores improved significantly.
• Significant improvements were also observed in restraint, eating concern, shape concern, and weight concern subscales (all p < 0.001).
• By study completion, 72% of completers had EDE-Q scores within the normal range.

Depression: 

• Beck Depression Inventory scores decreased significantly over the course of treatment (p < 0.001).
• Depression scores normalized in all study completers.

Psychological and behavioral outcomes: 

• Significant improvements were observed in body dissatisfaction, low self-esteem, personal alienation, anxiety, clinical impairment, and harm avoidance.
• Trust in hunger and fullness cues increased significantly.
• Mealtime distress decreased significantly.

Three-month follow-up: 

• Thirty-nine percent of participants continued ketogenic therapy after study completion.
• Symptom worsening occurred in 28% of those who maintained KT compared with 64% of those who discontinued it.

Conclusion

This feasibility study suggests that ketogenic dietary therapy can be implemented safely in adults with anorexia nervosa who are weight-restored or mildly underweight, without causing clinically significant weight loss. Participants experienced improvements in eating disorder symptoms, depression, and several measures of psychological well-being. However, because the study was small, included only women, and lacked a control group, the findings should be considered preliminary. The authors concluded that larger randomized controlled trials are needed to determine the effectiveness of ketogenic therapy and clarify its underlying mechanisms.