I don't know a certain answer to your question, whether eating one meal vs. three would make a difference to nutrient absorption. But--digestion can be a long process, just because you only briefly consume food, that doesn't mean that you also have a brief time for absorption of nutrients. A fair amount of mineral absorption, for instance, can happen in the colon, there are various studies that show that short chain fatty acids formed by the fermentation of soluble fiber etc. can increase the absorption of minerals there.

Also--without knowing the answer, it could just as easily be true that shorter eating windows improve absorption of nutrients. The potential uptake of a nutrient isn't a static thing, a high level of absorption will often lead to a downregulation of various transporter proteins etc. So that period of not eating can increase absorption of nutrients when you do eat.

There are studies with magnesium deficiency etc., in the deficient state, magnesium absorption is greatly increased, far beyond what would be needed for daily requirements in the replete state.


Even when people eat multiple meals a day, some nutrients may be mostly consumed at one meal. If your major source of magnesium, again, was spinach, would you think twice about eating all of your spinach at dinner? I doubt it. I really doubt that it's a problem. I can't give you a more certain answer without making something up.