To start, here’s a great article on what causes obesity (overconsumption) : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8450866/

Here is a great study on the major health risks of obesity : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6088226/

When it comes to studies on red meat, association is not very strong on red meat being inherently cancer-causing (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7015455/), and for those who are concerned, adequate fiber consumption seems to cancel out the risk: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4588743/

Processed meats are obviously great to avoid, and you should watch your saturated fat consumption just because it does nothing to help your LDL to HDL cholesterol ratio, but generally eating lean meat (red or not) isn’t going to be a problem for a normal healthy individual. It’s one of the most nutrient dense foods you can get. For someone like me who is trying to gain muscle, it’s an amazing protein source as well. For people who are trying to lose weight, lean cuts of red meat would be greatly assisting as eating nutrient dense foods while in a caloric deficit helps with hunger cues and makes you feel more satiated. To demonize unprocessed lean meat is just flat out wrong.