yes, 80% of your weight loss is attributable to your diet. Excersise is a great thing and will accelerate and help maintain a slimmer figure, but ultimately you need to identify what put you in the situation you're trying to get out of.
Start educating yourself about the food you eat. Open your pantry and read all the lables on what you eat, infact don't eat anything until you've read the label. Learn to identify ingredients you need to moderate... glucose/fructose, hydrogenated anything, corn syrup, dextrose, and anything that sounds like it shouldn't be there (like corn starch and sugar in low fat mayo....) The further up the list they are, the more of them are in the food. Also, when comparing, check the serving size the "nutritional Info" is based on so you're comparing the same portion size. Watch the fine print.... 50% less fat than what? Butter?
When you do groceries ONLY buy what you find on the perimeter of the store, don't go near the aisles.... fruit, veggies, whole grain breads (in restricted amounts) meat, fish, poultry, eggs, low fat dairy. Buy the best you can afford. Bargain foods are no bargain, cheap ingredients, fillers and water retention are all tricks food marketers use to manage to sell you more for less.... there are no free rides.
-Invest in some Whey Protein Isolate Powder and make your breakfast a smoothie with skim milk, a banana, strawberries and vanilla protein powder... good for you and it will keep you going.
-Eat 6 small meals a day, and make sure each one includes a Protein source. A hard boiled egg, a chicken breast, some tuna with lemon juice. You'll never feel hungry....ever
-Don't eat after 7 PM
-Don't ever go hungry
-Schedule a "me" meal once a week and have whatever you want (that's A big mac with fries and sundae, does not give you a licence to have 2 large pizzas with a 6 beer chaser...lol)
-No more soda....water (Crystal Light if you must)
-Nada on the fruit juice, 100% juice with no added sugar if you must, and 1 a day. (remember a glass of juice contains all the calories of all the fruit that were pressed to make it... would you eat 6 apples at a time? or a pound of grapes with dinner?)
That, in a nut shell will help you make some real changes in about 6 weeks. Promise.