On 1-jan-05, I weighed in at 245-lbs and my doc was half-joking about not seeing me anymore, saying that he was gonna take out life-insurance on me instead and retire when I croak. Being 5'5", that was a lot of heft to be carrying around. Yesterday, I weighed in at 175-lbs. Along the way, I've tried any and all types of "diets" out there, low/high-carb, high/low/no-fat, high-protein/no-protein, etc. I've found that it really didn't matter so much
what I ate as much as
how much I ate calories wise. The only consistent thing has been that I've eaten less than I burn off. But not all foods are equal, some foods have very low calorie-density and you can eat a lot, but others are very high in calorie-density and I'd just need to have a nibble or two of an small plate and I'd exceed my total calorie allotment for the entire day!
Now I'm back to a normal balanced diet with lots of veggies, fruits, grains & legumes. Total fat is about 400 calories total a day, protein about 200-400, and I adjust carbs from 1500-6000 calories a day depending upon how much riding I'm doing. Actually I don't watch it that carefully, I still do a lot of drinking, partying, going out to eat, etc. But I make sure I burn it all off the next day. If I've been especially bad, I'll just add an extra hour or two to my ride.
If you want to lose weight, it really comes down to the volume of riding and calories you burn off. Go slow and steady so that you can burn off the required number of calories. Going too fast and too early will just result in insufficient recovery and you'll end up hitting a plateau and getting discouraged, or even injure yourself. Have fun!