Table 1.  Fatty acids and calories in 100gs of uncooked lean meat  

Jo Robinson; Why Grassfed is Best:  A 6-ounce steak from a grass-finished steer has almost 100 fewer calories than a 6-ounce steak from a grainfed steer.  If you eat a typical amount of beef (66.5 pounds a year), switching to grassfed beef will save you 17,733 calories a year—without requiring any willpower or change in eating habits.  If everything else in your diet remains constant, you'll lose about six pounds a year. 

Research by Loren Cordain from Colorado State University and Bruce Watkins from Purdue University demonstrates that meat from grassfed animals is very similar to meat from wild game animals. This is not true for grain-fed animals. Compared to elk, deer, and antelope, feedlot beef  has  more total fat, saturated fat, and omega-6 fatty acids, but fewer health-promoting omega-3 fatty acids.  According to the research team, "... pasture-fed cattle are closer to values found in wild ruminants, and from a health perspective, the meat from these animals would probably be superior to meat from grain-fed cattle." (Cordain, L.; et al.  2002.  Fatty acid analysis of wild ruminant tissues: evolutionary implications for reducing diet-related chronic disease. European Journal of Clinial Nutrition 1:191.)  (See press release and abstractbelow.)

Dietary Recommendations for Children
A recipe for future heart disease?
article on fats in the diet from the Weston A. Price Foundation by Mary Enig, author of Know Your Fats, The Complete Guide to Understanding the Nutrition of Fats, Oils and Cholesterol.  Excerpt:

     What happens when children are put on lower fat diets? When researchers prominently associated with the American Heart Association fed children lower fat diets and measured some of the markers they consider important predictors of heart disease, they learned that these lower fat diets were causing the very problems they wanted to prevent. The children whose genes would normally have been producing the desirable light and fluffy form of LDL started to make the dangerous small and dense form of LDL (Dreon, MD et al, American Journal of Clinical Nutrition 2000 71:1611-1616). Thus the US dietary recommendations are likely to be causing heart disease, not preventing it.
Which Are Good Fats and Oils for Children? 
     ....Good fats are quality dairy fats from grass-fed cows, such as butter, cream and whole milk. Good fats are natural fats from properly fed animals, poultry, and fish. These animal fats supply true vitamin A, vitamin D and the proper cholesterol needed for brain and vision development. The animal fats also supply other fat soluble nutrients that support the immune system such as glycosphingolipids. Fish oils such as cod liver oil also supply important elongated omega-3 fatty acids as well as vitamins A and D. 
      ....Foods should be chosen so that they supply a mixture of these different fats and oils. No one fat or oil can properly suit all purposes, although many of the good quality animal fats come close. Children need enough of the stable saturated fats, they need enough of the monounsaturated fats or oils, and they need an adequate amount and a proper balance of the essential fatty acids, which come primarily from the omega-3 and omega-6 oils. 
Other Dangers
     ....One of the chief dangers of the US Dietary Guidelines is that they encourage parents to use substitutes for natural saturated fats, such as margarine and shortening. These manufactured fats are composed of partially hydrogenated vegetables oils, high in trans fatty acids. These are particularly dangerous for growing children as they can interfere with growth and the development of the nervous system, and affect sexual maturation and fertility. They can also cause cancer and heart disease.

Cave men diets offer insights to today's health problems, study shows

(Press release from Purdue University)

     WEST LAFAYETTE, Ind. – Eat meat. That's the dietary advice given by a team of scientists who examined the dietary role of fat in a study that combined nutritional analysis with anthropologic research about the diets of ancient hunter-gatherer societies.
     But there's a catch: To be as healthy as a cave man you have to eat certain kinds of fish, wild game such as venison, or grass-fed meat such as beef.
     The research was conducted by Bruce Watkins, professor and university faculty scholar at Purdue University and director of the Center for Enhancing Foods to Protect Health, and anthropologist Loren Cordain, professor of health and exercise science at Colorado State University and author of "The Paleo Diet" (John Wiley & Sons, 2002). Watkins and Cordain conducted detailed chemical analysis of the meats people ate 10,000 years ago and compared those results to the most common meat people eat today.
     They found that wild game, such as venison or elk meat, as well as grass-fed beef, contain a mixture of fats that are actually healthy for you, and, the researchers say, lower cholesterol and reduce other chronic disease risk.
     Recent studies have indicated that a healthy diet should contain a balance of essential fats. The two types of most concern are omega-6 and omega-3, and both are essential for proper nutrition. Omega-3 fat, which is often found in high levels in certain fish, has been shown to reduce the risk of cardiovascular disease, but too much omega-3 can increase the risk of stroke. Omega-6 fat also is an essential fat, but too much omega-6 in the diet can contribute to inflammatory responses associated with of chronic disease.
     According to Watkins, the analysis done at Purdue found that wild elk, deer and antelope from the Rocky Mountains region have greater amounts of omega-3 fatty acids and a lower – and therefore healthier – ratio of omega-6 to omega-3 fatty acids in muscle meats, compared to grain-fed beef. 
     "Both grass-fed steers and the wild ruminants have a ratio of omega-6 to omega-3 fatty acids slightly above two in meat. In other words, two parts omega-6 to one part omega-3," Watkins says. "That ratio is much lower than the ratios of 5-to-1 to 13-to-1 reported in previous studies for grain-fed steers."
     Watkins says the low fat ratio of wild ruminants and grass-fed beef is good news for people who need to reduce their cholesterol.
     "The fatty acid ratio in wild ruminants is consistent with the recent American Heart Association recommendation to increase the consumption of omega-3 fatty acids found in certain fish in order to reduce the risk of cardiovascular disease," he says.
     The results of the study were published in the January issue of European Journal of Clinical Nutrition. The research was funded by the National Science Foundation, the Purdue University Office of Research Programs and the Pope & Young Club, a national conservation organization.
     Analyzing the foods that people ate 10,000 years ago is not a flight of scientific esoterica. The researchers say this finding has important implications for what we eat today.
     Although 10,000 years ago predates all modern civilizations, it is a small blip in the evolutionary timeline of humans. Some nutritionists believe that by studying what people ate in the Paleolithic Era, also known as the Old Stone Age, they can determine the proper mix of foods for modern man.
     Cordain says anthropological nutritionists such as himself have studied the few isolated hunter-gatherer societies – such as the Nanamiut of Alaska, the Aborigines of Australia and the !Kung of Africa – that remained into the 20th century and found that modern maladies, such as heart disease, high cholesterol, obesity and diabetes, are rare in these populations.
     "Over the past several decades, numerous studies have found that indigenous populations have low serum cholesterol and triglyceride levels," Cordain says.
     This is despite the fact that their diets aren't going to reap praise from many modern nutritionists.
     "Previous studies by myself and colleagues had found that nearly all – 97 percent – of the world's hunter-gatherer societies would have exceeded recommended guidelines for fat," Cordain says. 
     Watkins says although this may be surprising to many people, it fits exactly with what research is showing about the importance of specific types of fat in the diet.
     "Current research is showing that, with the decline of fat in the diet, the amount of fat isn't as important as the relative amounts, or ratio, of specific fats in your diet. It's a qualitative issue, not a quantitative issue," he says. "By eating more of the good fat you can lower your cholesterol and reduce your risk of cardiovascular disease."
     This balance of fats has changed dramatically in the past century, he adds.
     "Generally, our modern diets, especially in the past 100 years, have changed to where we're consuming excess amounts of omega-6 fat. Omega-6 is found in high levels in many of the oil seed crops that we consume," Watkins says. "It's also found in the meat of the livestock that eat these grains, as this study shows."
     Watkins adds that this research suggests new ways for potential diversification in agricultural production.
     "Our study points out that there are opportunities for ranchers and producers to develop niche markets for grass-fed beef that fit consumer interest in beef products that deliver special nutrients," Watkins says. "There may also be branding opportunities for products like the Laura's Lean Beef Products."

Writer: Steve Tally, (765) 494-9809; tally@aes.purdue.edu
Sources: Bruce Watkins, (765) 494-5802; watkins@foodsci.purdue.edu
Loren Cordain, (970) 491-7436; cordain@cahs.colostate.edu

ABSTRACT
Fatty acid analysis of wild ruminant tissues: evolutionary implications for reducing diet-related chronic disease.  Eur J Clin Nutr. 2002 Mar;56(3):181-91. 
L. Cordain, Colorado State University, Bruce Watkins, Purdue University, M. Kehler, CSU, L. Rogers, Purdue, Y Li, Purdue
     Hypotheses: Consumption of wild ruminant fat represented the primary lipid source for pre-agricultural humans. Hence, the lipid composition of these animals' tissues may provide insight into dietary requirements that offer protection from chronic disease in modern humans.
     Method: We examined the lipid composition of muscle, brain and subcutaneous adipose tissue (AT) from 17 elk (Cervus elaphus), 15 mule deer (Odocoileus hermionus), and 17 antelope (Antilicapra americana), and contrasted them to wild African ruminants and pasture and grain-fed cattle.
     Results: Muscle fatty acid (FA) was similar among North American species with polyunsaturated fatty acids/saturated acids (P/S) values from 0.80 to 1.09 and n-6/n-3 FA from 2.32 to 2.60. Marrow FA was similar among North American species with high levels (59.3 percent to 67.0 percent) of monounsaturated FA; a low P/S (0.24—0.33), and an n-6/n-3 of 2.24—2.88. Brain had the lowest n-6/n-3 (1.20—1.29), the highest concentration of 22:6 n-3 (elk, 8.90 percent; deer, 9.62 percent; antelope, 9.25 percent) and a P/S of 0.69. AT had the lowest P/S (0.05—0.09) and n-6/n-3 (2.25—2.96). Conjugated linoleic acid (CLA) isomers were found in marrow of antelope (1.5 percent), elk (1.0 percent) and deer (1.0 percent), in AT (deer, 0.3 percent; antelope, 0.3 percent) in muscle (antelope, 0.4 percent; elk, trace) but not in brain.
     Conclusions: Literature comparisons showed tissue lipids of North American and African ruminants were similar to pasture-fed cattle, but dissimilar to grain-fed cattle. The lipid composition of wild ruminant tissues may serve as a model for dietary lipid recommendations in treating and preventing chronic disease.

Experts offer the skinny on search for healthy fat
Purdue News; February 2002
     WEST LAFAYETTE, Ind. – Although current research suggests that we replace some of the omega-6 fats in our diets with omega-3s in order to have a healthier balance of essential fats, that's easier said than done.
     Diets that are too high in omega-6 fats have been associated with chronic diseases, such as heart disease, arteriosclerosis, diabetes and inflammatory tissue disorders, such as certain types of arthritis. Balancing omega-6 fats with omega-3 fats in the diet, however, have been found to lessen these problems.
     As a result of these findings, the American Heart Association now recommends eating omega-3 rich fatty fish, such as sardines, salmon and albacore tuna packed in water, two times per week to increase the amount of omega-3 fat in the diet.
     But Bruce Watkins, professor and university faculty scholar at Purdue University, says you can find foods other than fish that also have healthy amounts of omega-3s.
     Lean meat, plus fruits and vegetables can also contain omega-3s. "Now there are also omega-3 enriched eggs that you can buy in the supermarket," he says.
     In the future, more foods will be available with omega-3s added. Watkins is conducting an experiment of feeding algae that is high in omega-3s to dairy cattle to increase the amount of this good fat in their milk. 
     "We collected the milk fat and made cheese, butter and yogurt that has high levels of omega-3," he says. "This research is one of the ongoing projects at the Center for Enhancing Foods to Protect Health." Watkins is director of the Purdue-based center.
     To reduce the amount of omega-6 fat in the diet, Watkins says to limit fatty meats and vegetable cooking oils, except canola, olive or flaxseed oil. 
     "Most of the margarine and vegetable spreads that we use have high levels of omega-6s. The cooking oils generally have high levels of omega-6, except canola and flaxseed oil," Watkins says. "So if you are concerned about the amount of fat in your diet, you shouldn't buy tuna fish packed in soybean oil, because the soybean oil would dilute the omega-3s in the tuna."
     For those who don't care to eat fish and consider red meat an essential part of every meal, reducing the amounts of omega-6s in the diet takes a bit more effort. Research by Watkins and Loren Cordain, professor of health and exercise science at Colorado State University, and author of "The Paleo Diet" (John Wiley & Sons, 2002), has shown that corn-fed cattle produce meat that is high in omega-6 fat. 
     But the same study, published in the January issue of the European Journal of Clinical Nutrition, reported that wild ruminants and grass-fed beef have an omega-6/omega-3 fat ratio equivalent to that of wild meat, which also is a good source of omega-3 fat.
     "This particular paper shows that wild ruminants such as deer, elk or bison have a better omega-6 to omega-3 ratio. We also found that these same healthy fat ratios could be achieved in beef with grass feeding," Cordain says.
     Watkins says this type of beef could become an important niche product for some people. "Those who have heart disease or high cholesterol would get benefits from eating this type of beef," he says.
     Grass-fed beef, also known as pasture-fed beef, should not be confused with organic beef or free-range beef, says Jo Robinson, author of "Why Grassfed is Best" (Vashon Island Press, 2000) and co-author of the best-selling diet book, "Omega Diet" (HarperCollins, 1999).
     "Most all cattle producers, organic farmers included, send their cattle to feedlots to be fattened on grain for market," Robinson says. "The organic farmers just fatten them on organic grain."
     Lewis Hunt, a purebred Angus producer in Pleasant View, Tenn., says grass-fed beef has a reputation for being tougher and less flavorful than regular beef. "What I've had before didn't have much fat in it, and so the taste wasn't there," he says. "I didn't think much of it."
     But Robinson says modern farming practices are eliminating these problems.
     "My guess is that most people who say they've eaten grass-fed beef and didn't care for it probably were served beef from a free-range cow or an old cull cow. This is going to be quite different from modern pasture-fed cattle," she says. "Modern grass-fed beef are raised on very intensely managed pasture. The cattle are moved from pasture to pasture regularly so that they have a steady diet of green grass. This gives them the nutrients they need, and it also allows them to fatten up. This is a very specialized type of farming."

Here is a fascinating discussion thread about the "caveman diet" and the role of fatty acids in human diets, maintained on the website of Dr. U. Ravnskov (The Cholesterol Myth) 
http://www.ravnskov.nu/cholskept.discuss.cavemen.htm