Here is an exert from wiki under excess protein consumption:
"Furthermore, as noted, protein provides the body with 4 calories per gram, and when there is excess protein intake, the body will utilize as much of it for energy as possible.[2] After that stage, the body will produce fat from the excess protein, turning it into fat cells."
Here's the link for more info:
http://en.wikipedia.org/wiki/Protein_(nutrient)
...okay, except you're still wrong.
A "normal" protein intake is about 70 grams per day. A "high" protein intake is around 130 grams per day. The highest intake you can really safely sustain is something like 250 grams per day. Big-time Zone dieters (who I think are crazy) use 1 gram of protein per pound as a reference, and that's about as high as protein intake can realistically get.
Any higher, and the ability of the body to actually process the stuff pretty much goes to hell and you start to run into toxicity issues.
Even at the most extreme levels of protein intake that the human body can realistically sustain, protein accounts for maybe 1000 calories out of the day. For comparison, the most stringent calorie restriction that is still considered safe is about 1200 calories per day. A normal human, depending on height, weight, and physical activity, takes in anywhere from 2000-3000 calories per day.
That is, even the highest levels of protein intake that your metabolism can reasonably sustain still fall
way short of your caloric needs, and they don't get anywhere near hitting an excess. The fact is that it
is not safe at all to get more than 40% of your caloric intake from protein alone. The bulk of your caloric intake always comes --
has to come, is absolutely
required to come -- from fat and carbohydrates, because that's what the body was designed to handle.
In a reasonable scenario, if a person who is consuming 2500 calories and 80 grams of protein per day decides they're going to eat an extra 50 grams of protein (and that's
a goddamn lot of protein), that only brings them up to 2700 calories per day -- a less than 10% change. This can and will be easily offset by a big reduction in hunger.
In theory, could you exceed your caloric needs through excessive protein intake? Yes, but you'll kill yourself long before you manage to do so.
tl;dr: excess protein leads to
all sorts of problems but it has
nothing to do with weight gain, also, please learn to math.