a cookie is still a cookie, so no.
Saphron,
there is evidence that P+C and P+F meals helps increase your insulin sensitivity, particularly if you lift heavy weights, and follow that workout with a P+C meal where the carbs are high GI carbs (which is why you might hear me mentioning dextrose as a good post workout carb). You can basically retrain the body to only dump significant levels of insulin at the right times.
P+C and P+F can also help fix nutrition partitioning (how protein, fat and carbs get used by the body) by only eating carbs just before, and just after your workout because that's when the body needs carbs the most.
research is starting to show that mixing Fat plus high GI/Insulin Index carbs promotes fat storage in many people.
lastly, an acquaintence of mine used to be insulin resistant, type II diabeties, on blood sugar meds, and was 90lbs overweight.
Now she looks like a lean goddess, no more diabeties, no more insulin meds...and she did this in her early 40's!
so between science trying to prove it, and real life 'testimonials', I'm currently a believer in not mixing big insulin carbs with much fat. a couple grams of fish oil with your oatmeal...fine. But sugary, fatty ice cream, french fries, etc....NO!