Cutting back on calories does not lead to bone loss, as long as you eat a well-balanced diet

Cutting back on calories does not lead to bone loss, as long as you eat a well-balanced diet , according to a new study.

Researchers tracked bone loss and weight loss in 46 healthy overweight men and women on four different diet programs. The participants' average age was 37.

The control group was told to eat a healthy diet. The second group was told to consume 25% fewer calories than they expended per day. The third group was instructed to reduce energy consumption by 25% per day through a combination of exercise and diet. Participants in the last group ate a low-calorie diet (890 calories per day) until they lost 15% of their body weight, then they went on a maintenance plan. The program lasted six months, and everyone got recommended levels of vitamins and minerals, including calcium. Diet plans included 30% fat, 15% protein, and 55% carbohydrates, as recommended by the American Heart Association.

Bone mineral density and blood markers of bone resorption and formation -- processes by which bone is broken down and regenerated on a regular basis -- were measured at the beginning and end of the study. There was not significant bone loss in the calorie-restriction groups compared with the control group.

Weight loss varied by group. The control group averaged a 1% weight loss. In the second group (consuming 25% fewer calories than they expended), weight loss was on average 10.4%. Weight loss was 10% on average in the calorie-restriction-plus-exercise group. The low-calorie group (eating 890 calories per day) averaged a 13.9% weight loss.

The researchers note that other studies with older participants following similar calorie restriction have demonstrated changes in bone mineral density in less than six months.

"Our data do not support the notion that extreme weight loss (more than 10 percent) over short periods (three months) has a worse prognosis on bone health than gradual weight loss achieved over six months by moderate calorie restriction with or without aerobic exercise . We speculate that in young individuals undergoing calorie restriction, minor adjustments in bone occur as a normal physiological adaptation to the reduced body mass," the authors write. They urge that additional research with longer time frames be done.


WebMD Health News
by Caroline Wilbert