I have to agree with Tokyo Joe here - there are no shortcuts. You have to be ready to commit to and follow through with a complete lifestyle change. Every waking moment may be challenging for the next few years. But if you really want to see the results you're seeking, it's like anything else, you have to really work hard for it, both physically and mentally.
It's my opinion that most of those "lose weight quick!" methods are more akin to scams and more likely to be detrimental to your overall long-term health and success and teach bad habits. Still, at the end of the day, the method is not nearly as important as fixing the mentality. Give a man all the knowledge and tools in the world and he will still fail without the proper motivation.
My own battle with weight in the past wasn't nearly so extreme as the OP's but the experiences have stuck with me over the years as an important series of life lessons and epiphanies related closely to self-discipline, time-management, and knowledge of nutrition & kinesiology. It's unbelievably easy to fall off the wagon and to fail and fall back into old bad habits. Weight management and health must become a constant, conscious effort to improve yourself until it becomes an effortless, seamless, natural part of your daily life, and even then, you must be unrelenting.
In highschool I was around 165-170 lbs (I'm 6'1), muscular, and involved in competitive sports. I was burning on average an extra 2000-3000 calories per day and consuming around 4000 and made it look easy. Once I was no longer going so hardcore, everything went to hell.
I took off as a freshman to college and quickly ballooned to about 180 in almost a single year (losing some muscle in the process) living on campus and eating basically chick fil-a and pizza hut and drinking sugary sodas every day. It didn't help that I barely had to leave my dorm to access junk food, the meals already pre-paid by my parents. Of course, my metabolism started to creep due to lack of exercise.
School wasn't going quite as planned and I took the next year off and lived with my dad. I eventually got a full-time job but was still not exercising or strength training for that period of time.
After that year, I went back to school where I lived off-campus and was eating like a poor college student, but I still was not exercising and gained another 15 lbs (losing even more muscle mass in the process) and I wasn't even drinking alcohol yet at this point in my life.
Hardly paying attention to my deteriorating physique, I didn't even quite realize how heavy (for me) I'd actually gotten until I came home to visit my family over summer break and saw my former boss who told me straight up, "Wow you've gained weight!" For whatever reason that struck a chord somewhere in me. After that uncomfortable conversation and looking back at some old photos it finally hit me that I was fat, to the tune of probably 30 extra lbs (195 was my heaviest). I noticed that even my face looked rounder now than it once did. I was never a fat kid growing up, so the experience was pretty terrifying.
Since I was extremely active growing up, it wasn't so difficult for me to understand the "what" and "how" of getting back into shape, but it was a grueling battle in my mind as I had become undisciplined. At that point, I was probably depressed too, but a determination to slim down somehow outweighed everything else (no pun intended). That strong, initial desire to "not be fat" finally helped me overcome my laziness and I purchased some running shoes and started using free weights again.
Now, it had probably been 2 1/2 years now since I'd done any serious cardio and the first "run" was the worst. I barely could manage to finish half a mile. I felt disappointed in myself and humiliated even though I'd become much less self-conscious over the years (I grew up pretty introverted). Deep down I knew nobody was really paying attention to me but I still felt like some fat ass, even though in reality that was a baseless fear and being 30 lbs overweight in the grand scheme of things isn't the end of the world. The self-conscious feelings I had started to dissipate and soon I no longer cared if anyone was "looking at me" while exercising outside.
But I kept at it and began running twice a week, even after I returned to college for school. By then I'd upped the distance to 3/4 of a mile, then 1 mile. Then I started improving my pace/speed, and improving substantially, and eventually was running up to 3 miles a day, 3 days a week.
The other side to my success was that I started paying far more attention to what I was actually putting into my mouth. Not exactly counting calories, but becoming more aware and making better choices and opting to make my own meals (far cheaper too). That included giving up most desserts, sodas, fatty, and most processed foods. I focused on "staying" away from those foods rather than go completely cold turkey, and it worked.
In less than 2 years, I was back down to a fairly respectable 170 lbs. The few "stretch marks" I noticed when I was heavier had disappeared by now and I was even lifting regularly and had packed on 5-10 in muscle mass, eventually trading another 5 lbs in fat for muscle - never quite getting "jacked" but still in great shape. Not too long after that, my foray into the dating world and many adventures with women would begin.
Over the next several years, my weight would see some minor fluctuations, but it wasn't until I got engaged and was struggling with another bout of depression (largely due to that relationship and some major work-related stress) that I ended up in the low 180 lbs range again. This time around, I was drinking a bit too regularly and had not prioritized exercise over other activities. Rather, exercise had become an afterthought, something I did rarely instead of part of my daily/weekly routine. I also had gotten a bit too lax with my eating habits. Now in my 30s, I had to have another tough, heart-to-heart conversation with myself regarding where I was and where I wanted to be. I knew you only had one shot at life and that if I wanted to be around to enjoy it I couldn't afford to fail again.
That was a little over 2 years ago.
Today, I'm back to my peak, hovering around 162-165 lbs and feeling better than I did the first time around. I weigh myself every morning and mentally track my own progress. I can actually see my abs again!
Since January, I no longer keep alcohol in the house and drink occasionally on the weekends. If something has sugar in it, I avoid it. I take my coffee black and turn down dessert at dinner. Lean proteins and nutrient-rich meals are the norm. "Fast food" isn't even on my radar - a once a month social experience if anything. If I do "snack" it's usually an apple or a banana. I don't even have to "think" about calories and yet I'm able to steer clear of poor eating choices by being aware and mindful of cravings and when I do choose to consume something. I've learned that all my meals are better planned ahead, instead of reacting to how hungry I was and engaging in "impulse eating." Self-discipline at work.
Although I'm still not nearly as big as I want to be, muscularly, I've packed on some healthy weight and know I finally have the exercise/diet balance down to a science.
I'm not a "qualified expert" but I can speak from my own experience and success. etwsake, I hope you can glean something useful from my story and apply it to your own situation. The key is your personal commitment to achieving your goals. No amount of advice in the world is going to help you if you don't actually go through with the actions and stay actively motivated and committed. You will likely have to find your own way that works for you. Set initial, mid-long term and stretch goals. Keep yourself motivated and stay positive whether you are making progress or slipping backwards at any point in time. Remember that most of what is likely holding you back is in your head. Focus on the results, and find a way to ignore anything and anyone that impedes your progress. They aren't important. Good luck!