Identify a meal that costs less than $10 and provides at least 500 calories, tastes great, and has a low energy impact, based on life-cycle analysis (LCA).
Here's an overview of LCA and an example analysis of an aluminum can versus a glass.
Autodesk Introduction to Whole Systems and Life Cycle Thinking
Can vs. Glass Life Cycle Assessment
There are many resources online to help you select what your meal should be, and I know you don't have enough time to get into as much detail as the can vs. glass example. Please start by using the Food Carbon Emissions Calculator. There's also a decent chance someone has already done an LCA for your specific meal choice that you can use as guidance. It's worth doing a quick Google search to check.
Post your LCA to the discussion forum using the calculated emissions from the Food Carbon Emissions Calculator. You'll probably need to add together several different calculations to get your whole meal. Here's an example of a good post.
LCA is a powerful tool for measuring sustainability and we're just scratching the surface here. If you're interested in learning more about LCA, the EPA's LCA 101 document is a good place to start.
For more information
Here are some energy innovation ideas related to food: Living LOCAL.