One of the differences is that the traditional Inuit's diet is very high in Omega-3 fats while our western diet is very high in Omega-6 fats. Science has shown that the ratio of Omega-6 to Omega-3 should be as close to a ratio of 1:1 and certainly no more than 4:1. Inuits are about the only peoples to approach the 1:1 ratio while we typically come in at 20:1 and the real junk foodists are measuring in at upwards of 50:1 ratios. A balanced Omega-6 to Omega-3 ratio promotes a homeostasis, non-inflammatory state in the body while a tilt to the high Omega-6 side will promote an inflammatory and therefore disease and degenerative state.
It's a bit of a far stretch to justify a western meat diet with the Inuit's mostly raw diet of fish and seal fat. Not only that, as you've stated they've had thousands of years to adapt to that diet.