Caffeine and weight?

Does caffeine have a effect on your weight? Can drink at least 200mg of caffeine a day help with weight loss? As long as you are watching what you eat and exercise 5-6 days a week. I was wondering because my brother drink like two 2 liter of mountain dew each day and eat junk like ramen noodles, burger king and pizza rolls. Who know when he last ate a vegetable or fruit? He so skinny and lazy he plays video game all day except when he at work.

I hate to tell you this, but he has a high metabolism, like me. Caffeine won't actually help you lose weight, but it will give you the adrenaline to do more exercises. Don't drink 2 liters, cause you'll die qucker. Haha, I don't know if you'll actually die quicker, but it can't be good for your health.

he has a higher metabolism

he must have awesome metabolism. i know drinking a lot of caffeine will dehydrate you, not sure of the effect on weight though.

Not sure. Regarding your brother: Why you running him down. At least he works. Do you?

He better be careful with the Mountain Dew, not good for the gums!
But to answer your question....he is male and you are a female.
Guys are naturally more muscular thats why they are stronger than us girls.
Being that he is more muscular, muscle has lots of blood flowing, thats why they are usually warmer than us girls.
So muscle=blood flow=warmth.
But no caffeine has nothing to do with him being skinny. Its because he has more muscle which is continuely burning calories. Start lifting weights and you will find out that you can burn calories even when not exercising. Besides lifting small weights help your body create calcium so one day when you are older your body will stand more unright and your won't be prone to get osteoporsis.
Females are naturally born soft, for caring babies which equals fat. Yep, Lucky us. But we have our things we can do that guys can't.
Hope this makes sense to you.
Don't worry, one day he won't be skinny. This kind of diet will catch up with him when he stops growing which uses up lots of calories too. Thats why they sleep a lot too.