That's such a bizarre and unscientific statement. People become obese and insulin resistant primarily from excessive consumption of carbohydrates, not from meat. Most people who try a carnivore diet actually lose weight. (I am not recommending that diet, but it is a fairly effective means of weight loss.)
A carnivore diet isn't relevant. The point is that excessive consumption of meat is a relevant part of many people's unhealthy diet, which ALSO includes excessive sugar and flour. It's not attributing the health harm solely to meat, but saying that it IS a relevant part of it.
How is it relevant? Meat consumption forms part of the energy balance, but in most cases reducing meat consumption isn't likely to make people less obese. In practice the reverse seems to happen due to differences in satiety and hormonal effects.
I ate first keto and then carniveore years ago - did put on weight actually. yes, including organs and looked for supplements when needed. Now that I am pescetarian (mostly veggies, though) and the weight slowly comes off while I feel noticeably better than before and health markers finally go into the right direction.
It is well known that the anti-meat and anti-animal-fat propaganda was funded by the sugar industry in the 1960s. Although I'm currently on a carnivore diet and finally seeing some health benefits after a long time experimenting and battling with debilitating health issues, I would not promote it either. The bottom line is that with the intense lobbying from both sides of the discourse, we've drifted really far from the original intention of nutritional science – to understand how our body processes foods and what nutrition will lead to best health outcomes. Fundamentally, I just want to do the best for my body and will gladly switch my diet at any point given enough data and consensus.
This is tough to do when certain groups are directly benefiting from you not being in an optimal health. At this point I've resorted to experimenting on myself and trusting my gut, body and instincts when it comes to food. Also, reading smaller, hopefully-independent studies looking at certain micronutrients and their utilization – it's quite interesting to look at Vitamin A vs beta-carotene, ALA to DHA and EPA conversion, anti-nutrients and many more.
