Too much food.
I've been saying for months that restaurants at least give us too much food by at least a third. Plates are definitely bigger nowadays, and when I get takeaway, I can usually only manage about half what they give me. Everyone I ask agrees with me, and I always see half eaten meals when out at restaurants. When I had a meal in the US at TGI fridays, I was astounded with what they expected me to eat, I thought it would easily fill 3 people. So that far I at least believe to be partly true. Having dinner last night I had a portion more in line with what I reasonably expect to eat and believe it or not I ate it all, and didn't feel hungry afterwards. If restaurants provided half the food, we'd pay half the price (well I can dream), end up with less waste, or less waist, and double the capacity.
I do agree with pretty much everything everyone says here too, the UK could probably feed most if not all its population locally if they'd stop screwing the farmers into the ground, and got more local market buying. Over in Oz, they have Farmers markets, which are just like supermarkets, only 'run' by local farmers and all the produce is grown locally. The government should start getting a clue.