I read this thread with interest. I am choosing a different approach to diet. My family has a strong history of heart disease. My father, a trim and fit individual, died of a myocardial infarction while hiking on the Appalachian Trail two weeks after his 50th birthday. Four of his five siblings also died prematurely of heart disease and/or strokes.
My brother died of heart disease at age 65, and my mother had two heart attacks in her seventies. She is currently in the end stage of Alzheimer's; the first symptoms of her dementia showed up right after her second heart attack, and we initially thought the dementia was a result of oxygen deprivation during the event.
My immediate and extended family members all consumed meat and dairy products. In my thirties, my annual physicals showed low HDL and high LDL, with borderline high total cholesterol. (I understand the limitations of using LDL-C as a benchmark and that measuring LP(a) may be a better indicator of risk. But I'm using LDL-C as a proxy, since I have about 30 years of longitudinal data with that metric.)
At age 50, I became a pescetarian, and my LDL dropped out of the high range. Several years later, I stopped eating fish and eggs, and cut out dairy except for cheese. In 2013, after several years on that diet, my total cholesterol was 159, my HDL was 67, my LDL-C was 84, and my triglycerides were 38. My primary care physician at the Mayo Clinic said I had reached the "you don't have to worry about heart disease" point. (She is not a cardiologist, but I still liked hearing her say that.
A couple of years later, I added fish and eggs back to my diet, along with a more liberal consumption of dairy, mostly in the form of yogurt and milk in coffee drinks. In 2016, my total cholesterol jumped back to 217, with HDL at 78, LDL-C at 129 (total nonHDL cholesterol at 139), and triglycerides at 49. I started cutting back on dairy and continued eating fish and eggs. Over the next two years, my total cholesterol and LDL-C dropped below borderline high but remained higher than I would like, given my family history.
Earlier this year, at age 67, I had my first coronary artery calcium scan. It came back with a score of zero, and I strongly believe that score is attributable to seventeen years of living on a mostly plant-based diet. A couple of months after I got my CAC results is when my brother died of a heart attack. The last picture he posted on his Facebook page the night he died was a picture of two ribeye steaks he had grilled for him and his wife. The irony was not lost on those of us who loved him.
I recently moved back to my almost-vegan diet. I still take fish oil, and I may continue doing that and/or eating salmon roe as my source of omega-3 fatty acids. I may also choose to eat salmon up to three times a week instead of, or in addition to, taking fish oil. I'll continue monitoring my lipid numbers, and try to add LP(a) and oxLDL to the mix.
I understand the argument that our ancestors probably ate meat and fish along with plants and tubers. I like to keep in mind, however, that evolution rewards those actions and alleles that keep you alive long enough to pass on your genes. It couldn't care less about genes and lifestyle choices that keep you physically and mentally healthy into old age.
I wish everyone well with the dietary choices they make. Each of us must make a personal bet with our lives on what we choose to eat, so it should be made with the best available evidence and consideration.