Hmm, though I somewhat agree that the environment would benefit if we ate less beef, I think changing our eating habits is more important for other reasons.
Many have already mentioned how we *can* eat a lot of meat and be healthy, of that I have little doubt. The problem isn't the amount of meat(or cholesterol(sp)) we consume, it is our lifestyle(also mentioned). If we eat like our grand-fathers, we best be doing what our grand-fathers were doing. If we are not, we will get fat, no need to discuss any further.
My grand-father also ate a lot. He was originally from Germany, so his diet wasn't the typical North American diet. Breakfast consisted of toast(buttered), cereal(hot or cold), juice, milk, coffee, eggs, bacon and/or sausage, stewed fruit or jam. I kid you not, eating at his house was like going to a banquet, at home it was a bowl(maybe 2) of cereal.
Lunch: Usually consisted of leftovers from supper(dinner) from the night(s) before. Often the leftovers were slightly altered from their original state, such as potatoes and vegetables mixed together and fried or meat put into sandwhiches, but lunch always had 3-4 different foods from most of the food groups.
Supper(dinner): 5-6 choices. Meat was always part of the meal, though not necessarily the main part.
A tossed salad made from fresh garden vegetables, leaf lettuce(not that crap "Iceberg" so called lettuce), fresh picked tomatoes, fresh picked cucumbers, green onions (fp), radish(fp), a hard boiled egg or some other variety of ingredients, to top that off some exquisite homemade salad dressing(if you haven't guessed by now, I loved those salads).
There were always at least 3 vegetables, string beans, broccolli, stewed tomatoes, peas, carrots, beets, turnips, squash, spinach, basically any vegetable you could imagine would eventually be served some night.
Meat: The meat could be almost anything. My grand-father had taught his 3 sons how to hunt when they were younger, so my uncles were constantly giving my grand-father meat. Venison, moose, caribou, elk, grouse, and various freshwater fish were as normal as chicken, beef, or pork. Eating at my grand-fathers house(although the credit must go to my grand-mother for cooking all this day-in-day-out for 50+ years) was always an adventure for me, a memory I hold dear(he passed away 2.5 years ago at the age of 90).
My point? Not only did my grand-father work hard all his life(even after he gave up his farm, he bought an orchard, after giving up that, he always kept a large garden and yard, he always was doing something physical), but he didn't eat crap! Go ahead, eat meat, but if you don't eat your veggies, your meat is always in the form of a burger and fries are your veggies, or you sit on your butt all day you are going to get fat and die!(prematurely that is)
It should be noted that there are even stories of smokers and drinkers who lived long healthy lives. The problem seems to go beyond certain things being bad for you. It seems that a lifestyle is associated with healthy or non-healthy living.