I am a big fan of the Harvard school of public health. I was reading this article on their website about the Paleo diet and came across this information about grass-fed beef.￼ Although some grass fed beef may have more omega-3 fatty acids than commercial beef, the amount that is produced in even the highest samples is still about 10 times lower than an equivalent amount of fatty fish.￼ ￼ in other words, there is a growing body of evidence that there is little or no upside to eating beef. At least not evidence that meets what Valter Longo calls the five pillars of longevity.￼
Grass-fed beef is often highlighted on the diet, which is promoted to contain more omega-3 fats than conventional beef (due to being fed grass instead of grain). It does contain small amounts of alpha-linolenic acid (ALA), a precursor to EPA and DHA. However, only a small proportion of ALA can be converted in the body to long-chain omega-3 fatty acids (EPA and DHA). The amount of omega-3 is also highly variable depending on the exact feeding regimen and differences in fat metabolism among cattle breeds.  In general, the amount of omega-3 in grass-fed beef is much lower than that in oily marine fish.  Cooked salmon contains 1000-2000 mg of EPA/DHA per 3-ounce portion, whereas 3 ounces of grass-fed beef contains about 20-200 mg of ALA.
— Read on www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/paleo-diet/
The other thing you often hear from many optimum nutrition advocates, especially those are influenced by Paleo diet pseudoscience is this concept of getting the ratios of omega-3 and omega-6 polyunsaturated fatty acids in the right ratios. Again, according to the Harvard school of public health: bb
￼One question that some people have had is whether the polyunsaturated fats, specifically omega-6 polyunsaturated fats, are pro-inflammatory. There’s a myth going around that omega-6 polyunsaturated fats are toxic and pro-inflammatory and bad for us. That’s based on zero data, really. And this study showed that omega-6 polyunsaturated fats were the best of all. In fact, they were what was driving the majority of the benefit of overall polyunsaturated fat and also total fat.