Yep. And not only will you still feel hungry (which makes sleeping and concentrating harder), but if you have to do a lot of physical activity (say, hike 20K and dig for a five or six hours) you'll burn that in two days.

Also, keep in mind, to some degree food and sleep can be used to balance against eachother.
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-IronRaven

When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.