“changing from a typical Western diet to one that includes more legumes, whole grains and nuts, and less red and processed meat”
My maternal grand parents were from Romania and always hired elderly Hungarian and Romanian men to work on their farm. Their diets for lunch and supper always consisted about 10 oz of red wine and meat of all kinds. Their breakfast almost always consisted of eggs and bacon or sausage. They all lived well into their late 80s and early 90s. Their secret? Hard work.
Sounds like low carb worked for them.