Grass fed meat gives more omega3 fats (like fish), grain fed gives more omega6.  The body processes them differently, with omega6 supposedly causing more of a insulin type response, or something along those lines.  But grass fed is pretty bland, I find personally.

A diabetes drug hailed as the new miracle weight loss treatment that will replace opioids as the big money maker for Big Pharma is simply some neuropeptides, which your gut bacteria will make for you for free if you eat enough fiber.  Recommended 38g per day for men and 30g/day for women.  Hard to get enough fiber without some sort of grains and bean legumes, and hard to get enough fiber without eating too much complex carbs to qualify as keto.

In any event, almost everyone agrees lots of fat and protein are necessary, and the typical western diet has too much simple carbs, processed food and sugars.