There is an exercise placebo effect. From Psychological Science via Overcoming Bias.
Although actual behavior did not change, 4 weeks after [a group was told their on-the-job routine satisfied the Surgeon General's exercise advisory, they] perceived themselves to be getting significantly more exercise than before. As a result, compared with the control group, they showed a decrease in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index. These results support the hypothesis that exercise affects health in part or in whole via the placebo effect.I'm sure I need not remind everyone that reading my blog satisfies the Surgeon General's exercise advisory. Keep reading and watch those pounds fall away!