About one month ago, I dropped Mountain Dew (and all pop/soda) cold-turkey. The only time I DO have pop, is when I have a mixed drink, and that's 7up/Sprite, about 3 cans per week. I used to drink 2 20oz Mountain Dews per day, for 20 years. Yes, I'm obese. I hope I start to see the effects soon of the drastically reduced sugar/fructose intake. After 1 month, I haven't noticed anything yet. (My wife's a health nut, and makes me eat pretty well also)
That's great news! However, if you just took those calories and displaced them elsewhere in your diet, you likely won't notice anything (unless the calories are protein-based instead).
Best thing to do is start using an app like LoseIt or MyFitnessPal like a total maniac and start observing your exact dietary intake. Use a food scale!!!
You'll start to notice where you're going wrong each day, and can spot trends after a few months. It's worth the hassle.
At the end of the day, calories are still most linked to your weight, which is your first and foremost problem. Your body composition can then be further aided by a proper macronutrient ratio (ie more protein), and of course general health with proper fruit and vegetable intake.
After that, let the carbs and fats fall where they may, whatever works best for you. Just note that it's easiest to do one or the other (low-fat or low-carb), but not impossible to be balanced if you're tracking well.
While it can certainly make a big difference dropping soda alone probably won't have the kind of results you're hoping for. I think when I quit drinking soda with every meal I lost something like two inches off my waistline -- significant but not really the difference between obese and normal weight either.
Just losing 2 inches would be a huge confidence booster for me. I'm 6'3", 285 pounds, and between a 40-42 inch waist. If I could get below 40's again, I'd feel so much better.
There is this japanese approach called kaizen, meaning one step at a time. You already made the first and hardest one - decide for a change.
removing sodas (and other corn syrup stuff) is amazing step, what about a bit more movement? try walk, start with shorter, make them longer over time. find something to enjoy on these changes, that helps motivation a lot.
be persistent, don't make petty excuses why to skip it, and give it all a bit of time. learn to enjoy sweat - it means you're doing something good for yourself ;)
Be sure that you are not substituting the loss of calories with different sources, like slightly increased food portions, more often snacks, picking food from fridge. Your body got used to extra calories it was getting so it might influence you to substitute that.
