Only the material economy. The economy would transform, to be one of Energy Generation, Intellectual Property, Entertainment, Health Care, Excercise and Weight Loss facilities.
We are already making the transition to the "Dream Society". This would just speed it up. The economic dislocations would be great, but the great thing about this, is since food could be printed by the government, it would reduce the cost of social programs. Who cares how much is given away if it's only costing you a few cents of energy as opposed to 20-30% of your salary.
Scary stuff. Look at us today, things are so easy for many in the developed nations that boredom is the base of most actions.
Although there are many that use physical activity to counteract it, for the large (pun intended) majority free time entails hours of mindless visual/aural entertainment that leads to overeating and obesity.
Indeed, that alone insures the results you envision, but I believe the great wealth potential in a medical solution to being overweight will lead to a method befitting our laziness. ;)
OTOH, the pessimist in me is screaming to point out that peaceful transitions of this order are rare, and it's probable that hundreds of thousands of poor, uneducated, unemployed and unemployable screaming for "More, more, more!" will cause many bad times prior to the survivors being suitably socialized into the more benign aspects and great potential of the new society.