"What should the cost of the grocery bill be for a male with high metabolism and is vegan?"
What the cost of the strict vegetarian diet for a male who's a vegan, will depend on what's bought. It can range from fairly inexpensive, easily from under eighty U.S. dollars, and up. There also a number of prepackaged foods that are calorie dense, that you can buy, that aren't expensive. The only drawback to many of those, is that they're either high in sodium, or high in sugars. However as stated the costs will depend on where you shop at, and your preferences.