I was a lacto-vegetarian (my diet included dairy products) from 1970 to about 1987, when I started eating fish, so I know from personal experience that a vegetarian diet can be both healthy and satisfying. For the record, vegetarians have a lower than normal incidence of heart disease and cancer and lower risks of obesity and diabetes. Vegans (vegetarians who exclude all animal products from their diets) can easily become deficient in omega-3 fatty acids, vitamin B12, and other micronutrients and will need dietary supplements.
Without knowing more about your health history, I can’t say whether the advice to begin eating meat was sound. Some people do not do well on vegetarian and vegan diets, especially if they do not pay attention to the principles of good nutrition; they may experience lack of energy and just not feel well. But I can tell you that you can get adequate protein from plant foods; legumes, whole grains, seeds and nuts. Soy protein is equivalent to the protein you would get from meat, chicken, fish or eggs.
If you do eat meat, getting it from grass-fed cattle is much better for you than the beef from animals raised on factory farms and fed grain (not to mention hormones and antibiotics). Cattle have evolved to eat grass; they are not adapted to digest grains, which wreak havoc with their digestive systems (one reason they need antibiotics on feedlots).
Meat from grass-fed cattle is lower in saturated fat than meat from cattle fed on grain. It also has more omega-3 fatty acids, vitamin E and conjugated linoleic acid - all good for human health. Incidentally, organic beef isn't necessarily grass-fed. The cows may be raised in pesticide-free pastures, but they are taken to feedlots and fed (organic) grain prior to slaughter.
Grass-fed beef is somewhat more expensive than the meat you're accustomed to buying in the supermarket, even though it is becoming more widely available. And it may vary in flavor from batch to batch, depending on where and when it was produced.
Give your new diet a reasonable trial - say two or three months - then decide if it’s doing enough good for you to stay on it.
Andrew Weil, M.D.