Well I went from 207 to 173 in about 8 weeks using a ketogenic diet. Many people say these are not safe, but the research shows that, if the directions are followed correctly, they are completely safe. Additionally, bodybuilders have been using ketogenic diets for decades during their cutting phases prior to competition.
The most common ketogenic diet is the Atkins Diet. The Atkins Diet (and any other ketogenic diet) involves eliminating practically ALL carbohydrates from your diet for a period of 2 weeks BUT eating as much (within reason) meat, cheese, eggs, and fat as one wants, then slowly adding back carbohydrates until one reaches a level where he or she is neither gaining or losing weight.
Here's the science behind it:
Normally, the carbohydrates in food are converted into glucose, which is used to fuel one's body and brain. However, eliminating carbohydrates from one's diet causes the liver to convert fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. When the body produces ketone bodies it is referred to as a "state of ketosis" (which is why these diets are called "ketogenic" diets)
The diet has just enough protein for body growth and repair, and sufficient calories to maintain the correct weight for age and height. The "classic" ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. This is achieved by eliminating foods high in carbohydrates (starchy fruits and vegetables, bread, pasta, grains and sugar) while increasing the consumption of foods high in fat (cream and butter).
The reason a person MUST eat fat on this diet is because if a person eats too few calories, that person's metabolism will slow down. So, a person still wants to eat somewhere between 1,300 to 1,800 calories a day (this is a rough estimate; the real figure depends on a person's height and weight. This was my estimate). Eating meat almost exclusively makes getting this many calories into one's system a bit challenging (think about it: 1 whole can of tuna, for example, only contains 200 calories). Also, eating 6 small meals throughout the day instead of 3 big ones keeps one's metabolism going, which also aids the process.
While on this diet one should NOT do heavy weight training because carbohydrates are required to rebuild muscle tissue that is damaged during these activities (NOTE: Bodybuilders do use ketogenic diets, but they actually use "cyclic ketogenic diets," which is unnecessary for your purposes). However, riding an exercise bike or vigorous walking for 15 - 30 minutes every morning BEFORE you eat will REALLY make the pounds disappear, and aerobic exercise/light weights are always good for a person.
When I did this diet, I followed it by-the-book. This meant for the first 2 weeks, I could only eat a MAXIMUM of 15 grams of carbohydrates each day. To put this in perspective, 1 slice of bread has between 15 and 20 grams of carbohydrates. I could eat no fruit, no grains (bread, pasta, cereal, rice, etc.), no milk, no nuts, absolutely nothing with sugar in it, and very few vegetables. The diet I did (Atkins) also recommends eliminating all caffeine since it often affects ones insulin levels (NOTE: eating carbohydrates creates insulin spikes that transport nutrients to fat cells to be stored, so insulin spikes are completely counterproductive during ketogenic diets). So I had no coffee, tea, etc. Finally, the diet required me to drink about a gallon of water a day; I was constipated a lot due to a lack of fiber; and I had a killer headache for the first 2 days while my body switched over from using carbohydrates to using ketones. However, I lost almost 20 pounds in that first 2 weeks. AND, I lost almost 20 pounds in 2 weeks by eating cheese, bacon, and spinach omelets, tuna salad with extra mayonnaise between cheese slices instead of bread, and steaks cooked in butter with bacon and cheese on top of them. This was WAY better than those no-food diets I had tried before. Anyway, during the 3rd week, I added nuts to my diet; in the 4th week, I added dairy; and so on...Remember, this is a lifestyle change, not a quick fix.
I did this diet because I had a fatty liver, and my doctor told me to try it. After doing this for 2 months my liver function test showed that my liver was very healthy, showing enzyme levels that were near the bottom of the healthy range (whereas they had been 3x higher than the top of the range before). AND, since my body was converting fat for energy, my cholesterol level actually went DOWN during this cheese/bacon/mayonnaise frenzy! I am actually healthier now than I've ever been, and as long as I remember that this is a lifestyle change, and keep doing light aerobic exercise a few times a week, I shouldn't have a problem with putting the weight back (and I haven't yet). I even have a cookie or piece of cake on special occassions...I just have to do it in moderation. So, this diet/exercise plan will work, but it takes commitment. You sound like you have commitment, so maybe give it a try!
The links below should be very helpful in understanding this type of dieting further.