I'm a fitness instructor at my local gym in NZ (as well as many other things). What we find a lot of the time is people going on fasts or cutting out foods that are actually good for them.
Low-carb diets are fine, but please don't cut carbs completely. Your body was designed to have them and you'll feel the effects if you don't. It's the reason bodybuilders get so grumpy the day of competition - carbs are your brain's fuel. It's also best to eat carbs for breakfast, so you have the rest of the day to burn them. It's not a good idea to eat them before sleep, since you're literally sitting on them.
People generally need more protein - it aids a lot in fat-burning. This should be take up the majority of your meals. Meats (chicken, beef, fish), dairy, eggs, nuts, oats - these are all great things to eat even if you're not exercising.
Also fats aren't bad, just saturated ones. Good fats like avacado and olive oil can help you add muscle and tone down.
Most weight-training will burn fat, though the best way is high-reps. Between 15-20 reps will generate lactic acid in your muscles to help slim you down. It won't build bulky muscles either, just lean ones.
Cardio is fine but bear in mind it eats muscle - which is vital to metabolism. I'd only recommend it if it's absolutely necessary, and still it's best not to run. Running is somewhat of a myth in the fitness world. It puts a lot of repetitive pressure on your knees. It will burn fat (as will all cardio) but it'll also take you on a short-cut to knee surgery. Bikes, cross-trainers and rowing machines are much better for your body.
Lastly...for the woman! Ladies, you don't need to be afraid of lifting, especially free-weights. If your concerned you're going to look like the guy next to you at the gym - you don't need to worry about that. Men have twenty times the testosterone of women, you simply don't have the genetics to get that big...unless you want to take steroids