I use Fage yogurt as an example, but if possible, I'd like a general answer that can apply to products that are similarly packaged (ice cream tubs, detergent, etc.).
Assume the consumer consumes 1kg of yogurt a week. Assume the consumer tosses everything into the recycle bin. Does he do more harm (to the environment) buying his yogurt in the 1kg tubs or in the 200g containers?
Almost certainly the 200g containers.
Imagine a cube of yoghurt (ugh!). Think about the amount of material that will required to fully encompass that cube. That is the 1kg container. Now imagine that that cube is partitioned into five parts, and think about the amount of additional material required to accomplish this. That is 5x 200g containers.
The only caveat that I can think of, in terms of straightforward material use, is that the 1kg container may be thicker - but I'm sure that in the vast majority of cases it is the more economical option.
This does assume that all other factors are equal: that the full 1kg is eaten every week, that having a larger container doesn't lead to the consumer having larger portions, and so forth.
Simon W is overall correct.
While when the size gets large enough the walls have to be thicker because of the weight involved, for small products, the problem is that they have to be strong enough for the handling machinery.
However there is an easy way to test this:
Weigh them. Empty of course. For each container wash it and weigh it. Don't forget the plastic sealer under the lid. There are good kitchen scales now that are accurate to about a gram or so. Weigh a stack of each and do the arithmetic.
Take into account too the variability in materials. Some materials, like tetrapaks are very hard to recycle. (Tetrapaks have a layer of aluminum foil, two layer of paper, and I think a layer of plastic.) The easiest container to recycle is a plastic polyethylene milk jug.
(In response to comment about the re-usability of glass: Until glass containers standardize on a small enough number of sizes, then re-using glass is going to be difficult.
The beer companies in Canada had it made: For years law mandated that the standard stubby beer bottle was the only one that could be used for in-Canada bottling, and the other were taxed extra. Stubbies did an average of about 6-8 trips. Once some company bought a legislature to change the law, it all fell apart. While we still have a 10 c bottle deposit and refund, the bottles are crushed and recast.
But this was a unique situation. There were breweries in every province, and almost all beer was only distributed in-province. So the return path for bottles was short.
The dairy industry could do this, and in a few places it does. (You can buy milk, cream and yogurt in glass containers in Vancouver) It also has the fairly short local supply and demand.
Most industries don't. If I buy applesauce, it comes from BC, or Washington State, or New Zeeland. If I buy barbecue sauce, not only does it come from a single plant somewhere, but they have their own custom bottle.
At present we buy three things in glass bottles: booze, garlic stuffed olives, and sauerkraut. Oh, and a specialty marmalade that my wive loves and goes through about 2 jars a year.
I've not seen vegetables in glass instead of cans for decades. Indeed, most of the time I buy frozen veg, as often being better than fresh in terms of nutrients.
