When will true results show?

Would anyone seriously consider taking advice off someone who can not write a sentence correctly. Seriously. Weight loss at any age (other than under 5 years old) is reccomended for the over weight. There are so many more health consequences in being fat than there are being thin (mind you, health consequences still exist). And its usually the fatter people who are telling the thinner to not loose weight.
Anyway, to answer the question, weight loss comes down to diet, exercise, or surgery. If your eating few calories, and exercising enough to burn more calories than your eating then you will loose weight. So, if your one meal a day is junk and fat then it may be that your eating more calories than you are burning through the day. Its not about how much you eat, its about what you eat. If you eat crap, then its harder to loose weight, and nutrient deficiencies may develop. Also, if your only eating one meal a day, your basal metabolic rate may go down; and the body may go into fast mode. This makes it harder to burn calories.

Three healty meals a day that are low in calories but high in nutirents and exercise is the best way. These meals may be oats and skim milk for breakfast; a salad sandwich for lunch; and a steak and vegetables for dinner.
The exercise you mention sounds fantastic, and combined with a low calorie balanced diet you may loose the weight you want, and feel healthy.
Perhaps go see a qualified dietitian for a meal plan.

100 lbs? How much you should weigh is by how tall you are, not your age.