Strength Training, Combat Training, or Run for the hills?

With your limited time I'd recommend go ahead and learn how to fight. I can tell you from experience its better to know how to fight than just to be strong. Also work on your fitness. Sparring takes an amazing amount of physical fitness and if your good enough to tag and move on him, he'll get tired very quickly and you can do what you want with him.

Most people if they arent in shape have trouble lasting 2 minutes in sparring conditions.

Try and get involved in a striking style of fighting. There's Martial arts for grappling that will negate his strength but you dont have time enough to be profitient in them. If you learn to strike, your first few months your going to learn the basic punches and kicks and learn how to avoid being hit.

I'd suggest kickboxing or just regular boxing.

Hopefully this isnt a bet between two enemies. I'm hoping your just to friends that need to flex your muslces a bit. If your enemies, dont fight, just walk away. If your friends and there is no ill intent kick his *** :)

Find a school that offers serious MMA training (not just on the side, but as part of their regular program). You will get well-rounded instruction on both standing (striking) techniques and ground techniques (grappling or jui jits su). Pretty much every fight ends up on the ground, so it's important to know what to do (at least how to get him off of you) if it does go to the ground.

Also, you need to amp up your cardio routine. You'll definitley have the upper hand if he's as fat as you say he is. He probably has almost NO cardio, so if you can just OUTLAST him in a brawl, that can win you the fight as well.

Make sure there are clear rules (no eye gouging, no groin kicks, no breaking just the little finger, ect.....) and make sure you know exactly how long the rounds are and how many rounds are expected of you. Don't just "punch until somebody wins." Three (2 minute) rounds with 1 minute in between would be great to start off with. If you think your cardio can handle it, do three 3 minute rounds. That will wear him out pretty quickly.

Good luck, my friend! Size does matter some, but technique is more important. Anybody can be beat at any time, even the "big guys." Train hard, fight hard, and have fun doing it.

Combat training is probably going to be your best option. Strength training will only help so much against someone with a lot more body weight to throw around and greater size and reach.

Even if you do manage to become as strong as he is, it won't help you as much if you are punching his fat stomach and large head. You need to learn how and where to strike, get some fighting techniques and learn to control yourself in a high stress situation so you don't panic and start flailing. Power comes from speed and technique more than muscle.

It would also really help to learn some ground fighting as well... a big guy may try to use his superior weight to get you on the ground in a hold or pin. Most of the techniques that make it possible for a smaller person to easily overcome a larger one take a lot of time to master... but the basics will be better than nothing.

If either or both of you are members of a dojo you should really check with your teacher. In a lot of dojos fighting outside of the school is not permitted. If this is a dojo thing I would not worry so much about winning or losing. Even if you lose the fight, if you realize that you did not do enough to accomplish your goal you really did not lose. Ask for a rematch and then go back to the drawing board and learn from the mistakes you made in the match. Keep it up until you reach your goal. This way you will grow and who knows you just both might have a blast at this and become good friends.

Depends what kind of fight. If it is a no holds bared bare knuckle slug pound and ground than discretion is the better part of valor..... head for the hills pronto! Size always matters all things else equal. I don't believe in fighting just to prove a point. If it is to test or improve skills, even sport I am for it. If it is just macho d*** waving please get a real life and go live it.

Six months is time enough to make a lot of improvement in stamina and speed. It is not nearly enough time to make a good fighter. I have seen some guys you would think are out of shape that train regularly a couple times a week that are extremely competent fighters. Don't be deceived by looks alone.

Learn as much as you can in the time you were given. You can actually learn a lot in 6 months. Use what you know in the fight.

Use multiple Strikes and don;t hold back. Go for the deadly strikes if its gonna help...you know like the eyes, throat, and groin.

Your best bet now is to find someone around his size and weight, get some protective gear, and start doing light sparring, every day. Nothing works at giving combat experience than real combat. You can try to get Krav Maga training or Semper Fu.

If not, you should probably run. I don't fight people heavier than I am, neither should you.

Everybody loses. If you do this fight you have nothing to look back on, or regret. Do this for yourself and you'll get yourself a whole bunch of experience and pride!

Win or lose, do your best and kick his ***.

Krav Maga is something u can learn in a relatively short time. Everything else takes much longer to learn and apply.