Scientists at Stanford University School of Medicine in the US compared two diets with the same amounts of fat and cholesterol, but with very different foods.
The conventional diet focused on cutting out saturated fat and cholesterol, while the second diet included lots of plant-based foods.
The plant-based diet proved by far to be the most effective; more than doubling the reduction of 'bad cholesterol' compared to the conventional diet.
"A meal of spinach salad, egg and oatmeal-carrot cookies is healthier for your heart than stir-fried lean beef and asparagus and low-fat chocolate chip cookies - even when both meals contain the same amount of saturated fat and cholesterol," say the researchers.
They found that the standard low fat diet produced, on average, a 4.6 per cent LDL decrease. But the plant-based diet more than doubled this figure, achieving 9.4 per cent reduction in LDL.
This latest study provides yet more evidence to suggest there are ongoing openings for food makers to develop, and successfully market, low-fat, weight-conscious foods.
And the new findings imply that food formulations could gain from stressing the power of plant-based foods in reducing fat, and cholesterol, in the diet.
Obesity is the bane of today's world. Increased consumption of more energy-dense, nutrient-poor foods with high levels of sugar and saturated fats, combined with reduced physical activity, has led to obesity rates that have risen three-fold or more since 1980 in some areas of North America, the UK, Eastern Europe, the Middle East, the Pacific Islands, Australasia and China, claims the UN-backed World Health Organisation (WHO).
The authors of the Stanford study claim their research "breaks new ground" by comparing two patient groups eating different foods but identical amounts of total and saturated fat, protein, carbohydrate and cholesterol.
"The two groups' different levels of blood cholesterol change are attributable to the different foods - dark green salads and bean burritos, for example, versus iceberg lettuce and frozen pizza - and not differences in saturated fat and cholesterol intake," write the researchers.
The randomised clinical trial included 120 adults, aged 30 to 65: all had moderately high LDL levels, between 130 and 190 mg/dL. Each weekday for a month, they visited a research dining hall for a specially prepared, carefully weighed, chemically analysed lunch or dinner.
The study required that participants maintain a constant weight so that any changes in blood cholesterol would be attributable to the diets themselves-not to any changes in weight brought on by the diets.
"The effect of diet on lowering cholesterol has been really minimised and undermined by a lot of clinicians and researchers.
"But we think part of the reason was that we weren't really giving diet a fair shake. We were so focused on the negative-just what to avoid-and not what to include," concluded Christopher Gardner, assistant professor (research) of medicine at the Stanford Prevention Research Center and lead author of the study.
Full findings are published in the 3 May issue of the Annals of Internal Medicine.