Is losing weight or exercise more important?

Select proteins (i.e., vascular endothelium growth factor [VEGF], plasminogen activator inhibitor type-1 [PAI-1] and pigment epithelium-derived factor [PEDF]) that are associated with building blood vessels and causing the spread of tumors were measured in the blood of 439 overweight and obese women participating in a 12-month diet and exercise trial.  The women were randomly assigned to either a control group, a dietary weight loss group, an aerobic exercise group, or to a group that was counseled on dietary weight loss plus aerobic exercise. Blood was collected at the beginning of the study and at 12-month follow-up. 

Participants randomized to the diet plus exercise group had significantly greater reductions in PAI-1 at 12 months compared with controls (-19.3% vs. +3.48%). Participants randomized to either the diet alone and the diet plus exercise groups had significantly greater reductions in both PEDF and VEGF compared with controls.  The changes in these proteins that occurred with weight losses of 8.5 to 10.5% of body weight, did not occur in women who were assigned to the exercise alone group, suggesting that weight management may be of utmost importance in controlling tumor spread. This is an assumption however, since none of the women participating in this study were diagnosed with cancer.

What does this information mean to you, or how can you use it?

While this study does not provide definitive proof that weight loss will help control cancer (especially since it was done in women who were cancer-free), it can be helpful in discovering the biological reasons why weight loss “works,” and keeps cancer at bay.  It is interesting that weight loss works far better than exercise in influencing these proteins in the blood.  Does that mean you should stop exercising and just reduce the amount of calories you eat?  Heavens no!  Exercise has many benefits and is important for your overall health. So keep exercising, and definitely make strides to keep your weight under control by making wise food choices.


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