Given that two-thirds of American adults are estimated to be overweight or obese, it’s highly likely that we’ve 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 body’s 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