Objective: This study tested a secondary hypothesis of the CALERIE trial (Heilbronn et al., 2006) that a 12-month period of intentional dietary restriction would be associated with an increase in eating disorder symptoms.
Design: To test this hypothesis, 48 overweight adults were randomly assigned to four treatment arms in a 12-month study: (1) 25% calorie restriction, (2) 12.5% calorie restriction and 12.5% increased energy expenditure by structured exercise, (3) low-calorie diet, and (4) healthy diet (no-calorie restriction).
Main outcome measures: Primary outcome measures for the study were changes in: eating disorder symptoms, mood, dietary restraint, body weight, and energy balance.
Results: All three dietary restriction arms were associated with increased dietary restraint and negative energy balance, but not with increased ED symptoms or other harmful psychological effects. Participants in the three calorie restriction arms lost significant amounts of body weight. The psychological and behavioral effects were maintained during a 6-month follow-up period.
Conclusion: These results did not support the hypothesis that caloric restriction causes increased eating disorder symptoms in overweight adults. In general, caloric restriction had either benign or beneficial psychological and behavioral effects.
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