Much of the discussion favoring source reduction (i.e., waste prevention) focuses on the kinds of materials used to produce goods and, especially, the packaging which surrounds finished goods. At the same time both the EPA and OTA reports called for measures to reduce waste at the source, they warned that care should be taken in banning materials until there is evidence that substitute materials would do the job as well with less waste and/or environmental damage.
What's actually in the solid waste stream? The Franklin Associates report done for EPA suggests something like the following: In 1960, the largest fraction of our waste stream included organic materials like grass clippings, leaves and discarded food. Now it is packaging, which has increased by 80 percent since that time ...the average American may throw away about 650 pounds of packaging every year.  (In the early 1900s, the average American threw away about 1,200 pounds of coal ash per year and the typical American city had to dispose of thousands of dead horses every year. That's offered just to put modernity in perspective in case someone is ready to get perturbed about 650 pounds of packaging every year.)
The Institute of Resource Recovery (that segment of the solid waste management industry which promotes incineration) of the National Solid Waste Management Association, argues that we need to substitute undesirable (emphasis added) materials that are used to manufacture consumer goods. "Plastics, inks, and cadmium that ultimately find their way into the waste stream. These and other substances make handling waste (i.e., burning waste) more difficult and expensive. Developing alternative processes or using degradable (emphasis added) materials would reduce the environmental burden of disposal."  A New York-based environmental group charges that "many kinds of packaging items are simply unnecessary" and that "based on a comprehensive review of a wide variety of packages and products undertaken for this Guide, it is clear that packaging waste and convenience/disposable items have contributed greatly to this (solid waste) crisis. (The packaging industry) has helped burden America with a waste crisis threatening local economies, the environment and the public's health."  Gene Pokory, President of Cambridge Reports, Inc, told a Washington, D.C., audience that "plastics could become the symbol of much that is environmentally bad." His polling firm found 57% of Americans believing that the growing use of plastics presented a serious environmental threat even to the extent that despite the benefits rendered by plastics, on balance plastics did more harm than good because of their nondegradability and lack of recycling. 
What portion of the material found in the typical MSW is packaging? A 1989 study prepared by Franklin Associates, Ltd., in conjunction with Dr. William Rathje of the University of Arizona's Garbage Project, determined the volume of various types of waste under landfill conditions and then applied their findings to an existing database that characterizes MSW components by weight. 
Packaging represented approximately 34% of the total volume of MSW generated in the U.S. Everything else accounted for the remaining 66 percent. (Given that some 85% of all waste still goes to landfills, what one finds in landfills is a reasonably good estimate of the over-all structure of MSW.) Of all MSW, plastic products accounted for 18% by volume and 7.3% by weight (Not surprising, given that the volume-to-weight ratio for plastics is 2.5:1.) Previous volume estimates reported by the media have ranged from 30% to as high as 70 percent. Of all packaging in the MSW, (34% of all MSW) plastics packaging accounted for 27 percent – making plastics packaging about 9 percent of total MSW volume.
Paper and paperboard packaging comprised the largest portion of packaging volume in MSW – representing about 16% of total MSW and 46% of the packaging segment. Metal packaging represented 5% of total MSW and 15% of the packaging portion, and glass packaging accounted for 2% of total MSW and 7% of the packaging portion.
Fast-food packaging – the target of legislation in many states anxious to avoid the need for siting new landfills (including states with landfill space to spare) – amounts to 14/100 of one percent (.0014) of MSW. This includes cups, plates, bowls, containers, and trays. Polystyrene foam used to make food trays and egg cartons accounts for less than 7/100 of one percent (.00066).
Ban all fast-food packaging and 21/100 of one percent of the waste going to landfills would be eliminated. 
Clearly if we could get rid of absolutely all packaging, the amount of waste landfilled or burned would decrease by approximately one-third. Getting rid of all packaging or, at least, what the National Wildlife Federation and other such groups call "excessive" packaging, would certainly make a dent in reducing the rate at which landfills fill up.
Unfortunately, no one has yet defined what "excessive packaging" means. Clearly if various groups are determined to attack "excessive packaging", one or more of them ought to provide hard examples of "acceptable" packaging beyond what the packaging industry is now
doing on its own .