The assumptions about heart disease and cholesterol and diet has thrown out all what passed for nutrition advice. Dietary cholesterol, for most people, has little to no relationship to the amount of cholesterol in the bloodstream, and even the whole HDL/LDL ration has turned out to be questionable (for example, they used to tell people to take Niacin, because it raised the ‘good’ cholesterol and lowered the ‘bad’ cholesterol which made the ratio better, the only problem is that when they did long term studies, getting the HDL/LDL ratio that way didn’t affect incidence of heart disease, they were treating the symptom, not the cause. It turns out the real measurement is the so called LDL particle count, and more importantly, what kind of particles they are, which the HDL/LDL ration doesn’t measure, it simply measures LDL particles as if they are all the same, when it is the 'big, fluffy" ldl particles stick to the artery walls, which in turn happens because of inflammation.
Likewise, doctors have been preaching the ‘low fat’ diet as being heart healthy, when studies have shown that not only doesn’t a low fat diet improve heart health. The last time I saw my doctor, he was telling me eat a low fat diet, avoid all fats, including oils and nuts, and even had the misguided advice that if time preparing meals was a problem, there were good low fat frozen entries out there, many of which are full of salt and sugar and other things, to make them taste better…
Even salt as causing heart disease and hypertension has come under serious question. One of the problems is that many processed foods are loaded with salt, but using salt in cooking your own food is not harmful. Worse, the salt substitutes they promoted, potassium chloride and such, were not healthy…
As someone else pointed, the medical profession is often like the Vatican, takes them a long time to change. My cardiologist was trying to get me to go on Lipitor, which I refused to do (I take red rice yeast, which is a statin, but is lower levels and more gentle), and I mentioned that I also take CoQ10, because the statin drugs wipe out CoQ10 which the heart needs, and he gave me this whole spiel that that wasn’t standard protocol, despite the fact that major studies indicated that statins could cause heart damage because of the lack of CoQ10 and many doctors in fact were recommending taking it. The researcher who said that fat attaches to the artery wall because the wall was scarred because of homocysteine (now fully accepted it is why we are supposed to take folic acid) was ridiculed and such.
As far as cooking for someone with heart problems, best bet is to prepare food naturally, things like lean protein (chicken, fish, grass fed beef), vegetables, and to a certain extent grains like rice and whole wheat, are fine, and to be honest modest use of salt in cooking is not going to hurt the person. I wish I knew back then what I know now when my dad had his problems, he I am almost certain would have lived a lot longer had he not taken statins and would have enjoyed eating, he took what doctors said back then to heart (no pun intended), and I think hurt himself.