I see problems with the point you’re making and the literature it’s based on.
The first study relies partly on self reported adherence which everybody knows is more than a bit flawed regarding diet adherence. If you’re not adhering, you’re not getting results.
Now the difference in the point I am making and where I think we differ:
Step 2 diet of the American Heart Association or its equivalent (<30% of total energy intake as fat, with 7% or less as saturated fat; ratio of polyunsaturated to saturated fatty acid >1.4; cholesterol intake <200 mg/day; and energy intake to achieve desirable body weight).
This is the intervention they analyzed which shows what they also imply elsewhere in the paper and what I think is what you are getting at:
They changed only WHAT the subjects ate
That’s a difference in definition because if we on here talk about diet, we not only talk about what to eat but especially HOW MUCH.
So I get it, you are fat, you eat too much and I tell you: just eat less of that! That may be sustainable but not particularly effective as you stated (10% reduction).
But if you’re fat and you change your ways, get lean, eat “healthy” food and not too much, I bet the reduction in cholesterol is way higher.
In other words, if you get to the root of the problem, the inability to take up LDL-C into cells and metabolize it, you’ll end up getting more out of the diet.
Dietary compliance might be expected to be better in patients at higher risk of cardiovascular disease, but the reduction in blood cholesterol concentration was similar in the five comparisons among patients with coronary heart disease
And this statement from the review shows something we all know, you can’t get people to change their ways for their lives, literally. Even if it’s just diet.
Edit: I’ll add some literature later
Edit 2: Literature
However, in six patients given treatment by diet alone (no colestipol), comparable weight loss (-6 +/- 1 kg) did not alter plasma HDL cholesterol or total triglyceride concentrations, but reduced total cholesterol (-9% +/- 3%) and LDL cholesterol (-11% +/- 3%) levels. These results suggest that weight reduction increases plasma HDL cholesterol levels only in those patients with hypercholesterolemia given colestipol but not in those given treatment by diet alone. Nevertheless, the effects of weight loss on plasma total cholesterol and LDL cholesterol levels were comparable in the two groups of patients.
So minus 6 kg (13 lbs) equaled a 11% LDL reduction. That’s a lot.
Now what if we go to the extremes?
What if a man with 450 lbs goes down to a healthy weight of 180 lbs?
I don’t know what his lipids were but I bet they were sky high before and in range afterwards.
I already made the point about sustainability but if people would get down to low BF and a healthy weight, I bet most would have good LDL and total cholesterol. They are just not willing to do it.
Edit 3: not trying to completely generalize because I read some studies that couldn’t confirm a LDL decrease because of weight loss alone. Some also were in the ballpark of unreals statements.
This even went against what I’m saying partly but there are problems with the study.
My point is: Get healthy. Do sports, eat good food and get your weight down and that will do it for most people. Not all, but the vast majority. Because we are not talking about public policy here but the advice for individuals that are dedicated enough to do what it takes.