Dieting does not have to lead to bone loss

Results of a study of dieters following four diet programs have shown that dieting does not necessarily lead to bone loss.

Leanne Redman and colleagues enrolled 46 men and women for the six-month-long trial. The average age of participants was 37. Participants were randomly assigned to one of four groups: Group 1, the control group, ate a healthy diet; Group 2 were required to cut calories by 25% from baseline energy requirements; Group 3 were required to maintain a daily 25% energy deficit via a combination of calorie restriction and exercise; Group 4 were placed on a low-calorie diet of 890 kcal per day until they lost 15% of their body weight, and were then placed on a maintenance program. All dieters received recommended levels of vitamins and minerals, including calcium.

Weight loss varied throughout the 4 groups, from an average weight loss of 1% of body weight in Group 1 (the control group) to 13.9% in Group 4 (the low-calorie group). There was no significant bone loss in any of the groups.

The researchers conclude: “Moderate calorie restriction, with or without exercise, that preserves calcium intake for 6 months leads to large changes in body composition without significant bone loss in young adults.” However, they add: “Longer studies which include assessments of bone architecture are needed to confirm that calorie restricted nutrient-dense diets have no deleterious effect on bone health.”

Redman LM, Rood J, Anton SD, Champagne C, Smith SR, Ravussin E, for the Pennington Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy (CALERIE) Research Team. Calorie Restriction and Bone Health in Young, Overweight Individuals. Arch Intern Med. 2008;168:1859-1866.