Consumption
Even though some foods are available to consume doesn't mean that they are sustainable foods. There are many factors that go into determining whether a food item is sustainable to consume, and it can be exhausting to balance and weigh every category. Below are a few important areas that you will want to pay attention to while determining whether your food choices are sustainable.
Distance
Situation
Many items that you see in your local grocery store have traveled a long way to get to your dinner table. These long shipping distances result in increased fuel consumption leading to higher greenhouse gas emissions.
A study on Sustainable Table suggests that between production and transportation, growing 10% more produce for local consumption in Iowa would result in an annual savings ranging from 280,000 to 346,000 gallons of fuel, and an annual reduction in CO2 emissions ranging from 6.7 to 7.9 million pounds.
Solution
The easiest way to address the concern of shipping distance is to try and buy as many local food items as possible. While growing food locally doesn't address all environmental concerns circling food production, reducing CO2 emissions by 6+ million pounds per year would be a great help.
Farming Practices
Situation
In order to keep up with population increases and market demands on food availability, many food producers have switched to industrialized methods of farming.
These practices often involve producing both crops and livestock in facilities that wouldn't be able to support the level of production without the aid of antibiotics, hormones, and pesticides. While these chemicals allow the farmers to keep a high level of production, there are often side effects that you don't think about when you are purchasing your food at the market.
The chemicals can runoff into the water supply, the large facilities use higher levels of fossil fuel leading to increased greenhouse gas emissions, and there are studies indicating that some of the hormones increase risk of cancer which has led to the European Union banning hormones in food production.
Solution
A way to reduce your use of factory grown food is to buy from local producers. Local producers often aren't the same size as factory farmers meaning that they aren't using as many chemicals to grow their crops.
Additionally, if you are purchasing from an Organic Farm, then you are safe from almost all synthetic pesticides and all antibiotics. This is because the USDA started the National Organic Program which has set regulations against these chemical additives.
Additional Resources
Sustainable Table - The two issues listed above are the most obvious issues surrounding food production, but there are many moving parts that should influence your food consuming choices. Sustainable Table has a wonderful set of information that should allow you to make the most informed decision possible.