Yeah the energy stuff is one of the reasons why I eat only a little meat - instead of a lot. Some meat - such as most small scale produced chickens and pigs are fed on food waste and scraps, which means eating them is actually creating food out of waste, and some cows and other animals are farmed on land that doesn't have enough nutrient to grow much crops without high amounts of fertilizers (synthetic have a lot of problems, and "natural" fertilizers such as manure are responsible for lots of food contamination, such as the current E. coli outbreak in Europe) - so that's the kind of meat I mainly eat.
Local vs imported is a complex issue. Some crops, such as rice and soy products are typically grown in bad places, leading to much environmental damage - so I try to eat rice grown in Asia rather than Australia, for example, and avoid soy in most instances. This means higher CO2 emissions from transport, but due to the amounts shipped, taking your groceries home by walking or non- fossil fuel means reduces your emissions more than buying only local food and driving home (of course all local and walking is best).
The cow CO2 thing is a bit misleading though, since animal emissions of CO2 and CH4 are a natural part of the carbon cycle, and the carbon was usually atmospheric a year before the cow re-emits it to the atmosphere (it was assimilated by the plants the cow eats). CH4 is increasing dramatically in the atmosphere, and is a strong greenhouse gas, but has a very short atmospheric half life (about 7 years, compared with CO2 at 5700 years), and is increasing due to changes in biomass - decreasing plant biomass to replace it with animal biomass - mainly destroying forests for grazing - not because of the number of cows directly. There's also genetic research going on aimed at producing cows that release their carbon as a solid, potentially leading to a food system that reduces atmospheric CO2 rather than being essentially neutral.