Now there's nothing you can do about the food in the fields or the food that's thrown out at grocery stores. Or even the fries at McDonald's that get thrown out after 7 minutes if they haven't been sold. But there is plenty to be done at your home.
According to US News the average American family throws away between $1,350 -$2,275 worth of food every year. So let's take the conservative estimate. With 100,000,000 households in this country at $1350 a year, ($3.70 a day) Americans willfully throw away $135 billion in food a year. Food has become so ubiquitous and cheap in this country that we rarely give it any thought. This can be a very expensive oversight.
All of this us will die one day and until that happens we will require x number of calories to keep us alive. The less that we have to pay for, the more we can save. Every scrap of food that gets thrown away because "we don't eat leftovers" costs you future savings. How much does this actually cost you?
Here's the scenario: if you're 30 and plan to retire at 65 and live until the average age of 80. You will take the savings of $1250 (even more conservative estimate since we all have to waste some food) and put it into a pretax matching retirement plan from your employer. You will have increased your net worth by almost $495,000 by the time you retire and almost $1,400,000 by the time you hit 80 (I <3 compounding). Note this is also conservative because it assumes that food prices won't increase and that you're an average household making $52,000 per year.
Another fun fact: if American households ate all of their food instead of throwing some of it out, then American consumers could completely pay off all of their credit card debt in 7.5 years. Stay thrifty my friends!