You need to:
1) Get out of the house and SEE YOUR FRIENDS! If anyone can give you the support and encouragement you need, it's the people you love and trust. Social isolation is dangerous in its own way, and spending all your time focusing on your weight rather than allowing yourself to have fun and live your life is just going to make things worse.
2) Look into therapy if you're feeling suicidal. I know you don't want to hear it, but talking does help if you find someone willing and able to listen. This is coming from someone formally suicidal with therapy as a big contributor to my recovery, so please trust me when I say this.
3) Talk to your doctor about your weight concerns. Crash dieting is extremely bad for you and it's too easy to just gain the weight right back. Your doctor can help you figure out a steady diet and exercise program that will allow you to lose weight at a healthy rate and make it easier for you to maintain your weight once you get where you want to be.
4) For the love of Pete, don't deny yourself masturbation. If it's something you enjoy doing, cutting it out entirely will only make you more miserable. Self-denial is yet another unhealthy behavior.
5) Try looking into hotlines or online support groups, so that you can have someone to talk to at any time.

Truly, you're going about this in the worst way possible, and it makes me worry tremendously. While all of us here at Eden are happy to provide emotional support and advice, there's really not much else we can do. I know it's hard to reach out, really I do, but you're not going to get better or reach your ideal weight by shutting yourself away.

I second everything Rin (aka Nire) said.

It's important to lose weight in a healthy way. It's going to take time and effort and you will need your loved ones for support. They will be the best thing to help keep you motivated.

You can join a weight loss group like weight watchers. They not only teach you healthy eating habits that you can maintain after reaching your goals but have a reward system for exercise. There needs to be a balance between healthy eating and being active.

Rather than withholding masturbation, try a reward system. For example, for every 10lbs lost buy yourself a new toy. That will make the journey more fun and you won't get bummed out.

Try talking to someone about any bad thoughts you're having. It helps to talk and may give you some perspective.

Get out and see the people you care about. This will be your motivation to keep going.

Melan!e and Rin (aka Nire) gave great advice. I'd def listen to them. I do have advice on your concern for weight loss, but I don't think it's possible, and certainly not healthy to lose 40 lbs fast. Experts say you can lose between 2-3 lbs a week and still be healthy, so that means you should expect to take at least 14 weeks, probably 20 to lose that kind of weight (which is still pretty fast). That said, what you should do is figure out your daily calorie needs using a metabolic calculator, there are plenty online: link and then count your calorie intake to make sure that the calories you consume are less than you need. Exercise is also key so find something you enjoy and keep doing it. If you just walk a few miles a day that will help (you can do it early in the morning if you are embarrassed). It's often smart to purchase a good scale so you can track even small progress and feel good about it, whether it's half a pound, or a tenth of a pound it shows that you are going in the right direction and that should encourage you. Probably the easiest way to be discouraged is to want to lose weight in a hurry. Instead take your time; it sounds like you want to make a lifestyle change and that's great but no one can turn their whole life around in a matter of days or weeks so just feel good that you are motivated to go in the right direction and encourage yourself to keep it up for as long as it takes. Always remember that it is possible, other people have done it and that means you can too.

You've been given some great advice! You need a lifestyle change, not lost weight asap. Don't focus on the scale, focus on the measurements. Give it time, don't give up when you aren't losing as fast as you're hoping for.

Okay, first off I'm going to go ahead and agree with what everyone else has said. I know you don't want to work on mental health, but if you don't your self esteem will still be low even if you lose the 40 pounds.

That said, I gained 70 pounds when I was pregnant. I lost most of it in about three months using Nutrisystem and P90X.

I've gained about 20 recently from medications. I'm now using My Fitness Pal (which is an iPhone / iPad app but also has a website you can use). It tracks calorie intake and exercise. That should help give you an idea of what your intake is and where you can cut back. I'm also making sure to take at least a short walk each day.

Really though, please see a doctor if you're feeling suicidal. That's the most important thing. Your life is more important than a number on a scale. Once your head is in the right place, losing weight will be much easier.

I agree with all of the above.
I was doing good losing weight, lost 15lbs in 2 months then my flat foot condition caused me to have problems in one foot needing surgery and non-surgical treatments were tried at first so I have not been active for months and completely off my feet for 2. I start walking tomorrow but I don't know how long until I can be active like I want.

I was going to the gym, 3 days a week. I did 30 to 45 mins of cardio and 15 of weights.

If a gym membership isn't a possibility I cannot recommend Taebo enough. I'm talking about the old school VHS basic workout that is about 20 or 30mins long. I found it on ebay for about 4 bucks that includes shipping. I don't know if they have a DVD version or not since the covers are different and I never looked into it. If you are interested in it, shoot me a message and I can link you to the ebay auction since I don't know if we are allowed to post ebay links in the forum. But before I had a drivers license I really wanted to lose weight in high school and I did this and it worked! Plus you kinda feel like a badass with those moves you learn.

PS: losing that amount FAST just isn't a reality, it takes time and that is normal. And stay away from the diet pills, they are just bad news, trust me, I know from experience.

I see that most everyone is concerned with my mental state, but that's not necessary, since i'll be fine when i lose this weight. That's why i HAVE to focus on losing the weight!

I lost 60 lbs. in about 2 months before. The only reason i gained it back is eating too much junk food. I'll do it again and this time I won't mess up.

It is your mental state that is putting you in this position. That is why we are worried about it, we have been there and some of us have come back from it, others are working on it. If your mental state is not healthy, the rest of you will not be either!!! You are making the weight an obsession-- not a goal. An obsession is inclusive and exclusive, hinging everything in your life on and putting the rest of your life on hold whereas a goal is a task to work towards while still living life, enjoying the things that make you happy and success adds inner self confidence mentally. I know that you are using the weight as an excuse to isolate yourself and allow your fear to run your life, once you lose the weight you will find another excuse to isolate yourself. Would you want someone you love and care about to live in this manner????

Lecture is over. Please get mental help, join a weight loss group and start taking baby steps to socialize again. Get to the bottom of your fear and start living to make yourself mentally happy. I care about you and want you to be happy, healthy and productive!! Message me, please, I remember reading another post from you about needing true friends. I think I answered that one as well.

As a man weight just melts right off. I lost 50 lbs. running, eating better, and a little weight lifting.....lots of cardio. Stay away from surgery and pills. You need to work out everyday!!!!! and cut out high calories in your drinks like soda and juice.....only drink water no calories. You have to want this for yourself and you cant avoid going out you are 19!

Wonderful advice everyone! My son was put on a diet today per the doctor. I'm going to take some of the advice posted here for my family.

I really wish you the best but, please listen to some of the advice being posted in this thread.