The standard American diet is composed of 70% plant-based foods, which is the same ratio found in the Mediterranean diet which is lauded as one of the most healthful.
It's not the meat that's causing the issues, it's the processed plant foods and plant-derived oils that destroy one's health on a western diet. Or in other words, the horrible food quality. Any diet that doesn't include processed plant foods and oils will be an improvement from one that does, regardless of whether it includes meat.
I'm asserting that it's harder to be nutrient deficient given a meat/fish-based diet. The only "work" in this diet is not eating too much.
> western diet is strongly linked to all of our most deadly diseases
Mostly due to overconsumption, not due to the composition of the diet. Controlling for caloric intake eliminates most differences in health outcomes between the various diets, assuming no nutrient deficiencies are present.
I'll admit it's currently not that easy to follow a strictly plant based diet if you mostly eat in restaurants and don't live in a first tier Western city.
If you're willing to do your own shopping and mostly eat at home it's actually not only easy but really enjoyable to take back control of your health and what you eat.