No one would confuse wanting to bulk up with wanting to get fat. But in reality, the means to either end are pretty similar. Done the wrong way, trying to bulk up just leaves a guy flabby with no added muscle to show for his efforts. So if you're looking to gain weight — muscle and heft — you have to be strategic. "It has to be put together just like any successful business plan," says Jim White, dietician and American College of Sports Medicine exercise physiologist. Here's your guide.