A low carbon diet refers to making lifestyle choices to reduce the greenhouse gas emissions (GHGe) resulting from energy use. It is estimated that the U.S. food system is responsible for at least 20 percent of U.S. greenhouse gases. This estimate may be low, as it counts only direct sources of GHGe. Indirect sources, such as demand for products from other countries, are often not counted. A low carbon diet minimizes the emissions released from the production, packaging, processing, transport, preparation and waste of food. Major tenets of a low carbon diet include eating less industrial meat and dairy, eating less industrially produced food in general, eating food grown locally and seasonally, eating less processed and packaged foods and reducing waste from food by proper portion size, recycling or composting.

In the U.S., the food system emits four of the greenhouse gases associated with climate change: carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons. The burning of fossil fuels (such as oil and gasoline) to power vehicles that transport food for long distances by air, ship, truck and rail releases carbon dioxide (CO2), the primary gas responsible for global warming. Chlorofluorocarbons (CFCs) are emitted from mechanical refrigerating and freezing mechanisms – both staples in food shipment and storage. Anthropogenic methane emission sources include agriculture (ruminants, manure management, wetland rice production), various other industries and landfills. Anthropogenic nitrous oxide sources include fertilizer, manure, crop residues and nitrogen-fixing crops production. Methane and nitrous oxide are also emitted in large amounts from natural sources. The 100-year global warming potentials of methane and nitrous oxide are recently estimated at 25 and 298 carbon dioxide equivalents, respectively.

A carbon diet refers to reducing the impact on climate change by reducing greenhouse gas (principally CO₂) production.

Individuals and businesses produce carbon dioxide from daily activities such as driving, heating, and the consumption of products and services. To reduce the effects of climate change, we could reduce our carbon output by going on a carbon diet.

There are references to the use of the term carbon diet in several publications.

The term "carbon diet" is used in the book Gore: A Political Life

"And many scientists and economists maintain that the costs of adapting to any change are both easier to achieve politically and more efficacious scientifically than trying to avoid the problem through a crash carbon diet."

Deborah Jones from The Globe & Mail newspaper writes "It's week two of my family's "carbon diet" -- a Globe and Mail assignment to see how my family of four adults can cut its greenhouse-gas emissions to match the provincial goal of a 33-per-cent reduction..."

This differs from a low carbon diet which refers to making choices about eating that reduce greenhouse gas emissions.

A Low-Carbon Economy (LCE), Low-Fossil-Fuel Economy (LFFE) or Decarbonised Economy is an economy that has a minimal output of greenhouse gas (GHG) emissions into the environment biosphere, but specifically refers to the greenhouse gas carbon dioxide. GHG emissions due to anthropogenic (human) activity are increasingly either causing climate change (global warming) or making climate change worse. Scientists are concerned about the negative impacts of climate change on humanity in the foreseeable future.

Globally implemented LCEs, therefore, are proposed, by those having drawn this conclusion, as a means to avoid catastrophic climate change, and as a precursor to the more advanced, zero-carbon society and renewable energy economy.

Nations may seek to become low-carbon or decarbonised economies as a part of a national climate change mitigation strategy. A comprehensive strategy to mitigate, if that is possible, climate change is carbon neutrality and geoengineering.

The aim of a LCE is to integrate all aspects of itself from its manufacturing, agriculture, transportation, and power-generation, etc. around technologies that produce energy and materials with little GHG emission, and, thus, around populations, buildings, machines, and devices that use those energies and materials efficiently, and, dispose of or recycle its wastes so as to have a minimal output of GHGs. Furthermore, it has been proposed that to make the transition to an LCE economically viable we would have to attribute a cost(per unit output) to GHGs through means such as emissions trading and/or a carbon tax.