Check this out:

Absorption Increases by 50% When Vitamin D Is Taken with Biggest Meal, Study Finds

I've read several books on Vitamin D, but don't recall one author stressing the importance of when to take supplements.

I'd bet we'd see the same type of results for CoQ10 or any other fat-soluble supplements if taken with the biggest meal of the day.

Perhaps the more important issue, however, is how much fat is in your meal. If your biggest meal of the day has very little fat, I'm not sure how much D3 or whatever will be absorbed. A lot of consumers have been advised to avoid fat.