Given that two-thirds of American adults are estimated to be overweight or obese, its highly likely that weve been advised at one time or another by our doctors to lose weight. But a new study published in the American Journal of Physiology Regulatory, Integrative and Comparative Physiology says that advice may not be enough to get us down to our ideal weights.
We need exercise, too.
In the study, researchers at Oregon Health & Science University placed 18 female rhesus macaque monkeys on a high-fat diet for several years. They then returned the monkeys to a normal monkey diet that was lower in fat and approximately 30 percent lower in calories. The monkeys weight and activity (using an activity monitor worn on a collar) were tracked for 30 days. After 30 days there was no significant weight loss. However, there was a significant drop in activity.
In the second month, calories were reduced by another 30 percent and physical activity diminished even further.
A comparison group of 3 monkeys was also placed on the normal, lower-fat monkey diet and was trained to exercise for 1 hour daily on a treadmill. In contrast, this group lost weight.
This study demonstrates the bodys protective mechanism for conserving in response to sudden calorie reduction. The researchers suggest that the more effective path to a healthy weight is a lifestyle program that includes both a healthy diet AND exercise.
Read the study abstract at http://www.ncbi.nlm.nih.gov/pubmed/20071608