This has got to be one of the strangest abstracts I've read. Because it's only an abstract most of the really interesting information, like insulin levels, lies hidden in the American Journal of Clinical Nutrition.
It's a crossover design so all people acted as their own control group. The study participants were chosen as having low HDL cholesterol and/or elevated triglycerides, two classic markers of insulin resistance. The purpose of the study was to see which of two interventions decreased the participants "risk factors" for heart disease (ie it was a short study with no body count). Both interventions reduced some of the dreaded saturated fat from the of 35% of total fat in the Average American Diet (usually termed the Standard American Diet or SAD, but...). Excellent move to improve lipids wouldn't you think? Except replacing the saturated fat with carbohydrate decreased HDL by 7.2% and using monounsaturated fat decreased HDL by a mere 4.3%.
How about triglycerides? Well the MUFA substitution did nothing to triglycerides (the phrase used is "tended to be lower", meaning no change unless viewed through rose tinted spectacles. I hope their statistician resigned over this phrase, or has since been sacked). The use of carbohydrate cranked up triglycerides, but by how much it doesn't say, just "significantly".
But the best results were lipoprotein(a). You know, that BAD lipoprotein with the genetically pre programmed blood level. It got un-genetically reprogramed upward by 20% in the increased carbohydrate period. The MUFA feeding did far better on this front, MUFA replacing saturated fat only increased lipoprotein(a) by 11%.
In the murky world of lipid belief these changes are, I understand, considered to be BAD. All of them, except perhaps that non-changed triglyceride value in the MUFA feeding period.
Luckily the calculated LDL-C went down, although goodness knows what happened to lipid particle size and numbers (actually you can pretty well assume they got worse, especially the small dense LDL during the carbohydrate period). The abstract certainly makes no suggestion the researchers considered anything other than calculated LDL. It was enough that this reduced a little to allow the DELTA researchers to claim improved CV risk for both interventions.
Actually they claim that MUFA "improved" cardiac "risk" more than carbs. Even if you believe their LDL stupidity, can anyone really believe that a 6.3% reduction is either statistically or biologically "better" than a 7.0% reduction? In your dreams, cardiologist.
What came out rather well was the Average American Diet, SAD or not.