Contrary to conventional wisdom, weight management (and loss/gain) is not all about caloric deficit (intake vs.burn). For the past 150 years or so, methodologically sound scientific research on diet and/or weight management has shown rather consistently that a low carbohydrate diet is not only the healthiest diet for most people, but also best for weight maintenance. (For an excellent and robust review of the scientific literature on diet and nutrition - including an analysis of why the low fat approach to diet was erroneously espoused by the U.S. health establishment for the past 40 years - see the book "Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health" authored by the well-respected science journalist Gary Taubes and first published in 2007.)
The diet you have described - yogurt (low fat with sugar, a simple carb) and some grain (high carbs) for breakfast, brown rice (high carbs) for lunch, and soup (likely source of carbs, especially if not broth) and yogurt and fruit (high sugar) for dinner - is not only unhealthful but also a recipe for weight GAIN.
The conventional wisdom still being espoused by most among the medical establishment - that one should acquire 60% of daily caloric intake from carbs, 10% from proteins, and 30% from fats - as the proper mix for good dietary nutrition is now (finally!) being recognized as the outgrowth of atrociously bad science conducted during the 1950s and 1960s. Next year, the FDA is expected to release new guidelines recommending a diet consisting of 30% carbs, 12% proteins, and 58% fats. While every individual's dietary needs do vary, this new guideline is probably fairly close to right for the vast majority of people. Among the exceptions is the person who is a very serious or professional athlete; these folks typically need a greater share of carbs in their diets.
So, for all but the most serious of athletes, if you want to lose weight, the intelligent approach is to stop counting calories - I can hear the screams from most forum members who have been brainwashed into believing otherwise - and instead to start cutting the carbs. It really is that simple. (If you are interested in losing weight quickly, you might consider trying the full Atkins Diet program plan.) On any sensible, carbohydrate restricted diet (e.g., the later phases of the Atkins Diet, the South Beach Diet, most versions of the Paleo Diet), you almost surely will lose weight and your blood lipid panel will shift with HDL ("good cholesterol") levels increasing, large fluffy (beneficial) LDL levels increasing, small dense (deadly) LDL levels decreasing, and (unhealthful) triglyceride levels decreasing. In other words, your health will improve.
Also, it is important to understand that the type of carb calories that one consumes very much does matter. You need carbs in your diet to remain healthy, but you should choose your carbs wisely. You should avoid simple carbs (like sugar and refined grains) and prefer complex carbohydrates (like nuts, all salad vegetables other than carrots, string beans, leafy vegetables, and cruciferous vegetables). Starchy vegetables (e.g, root vegetables like potatos and beets, beans/legumes, and corn) and whole grains should be eaten only occasionally and in moderation. Fruits are healthful, but only if eaten in limited amounts. Really high sugar fruits (e.g., apples, pears, bananas, peaches) should be eaten rarely, if at all, while high sugar fruits (e.g., melons, grapes) should be eaten only occasionally and in small quantities; rather, you should prefer berries (low sugar), cherries (moderate sugar), and citrus fruits (moderate sugar). Radishes and onions - which are root vegetables - are the exceptions to the avoid-root-vegetables rule; they are fine to eat since they are not starchy.
Though being active certainly helps with weight management, weight loss has much more to do with what you put in your mouth than it does with activity. Exercise is hugely important for other health reasons beyond weight management, so don't think I am suggesting you don't need to be exercising. But, exercise tends to add muscle mass and muscle is denser than fat so, as you lose body fat as a result of proper diet, the added muscle mass acquired from exercise tends to offset the weight lost in body fat. So don't worry too much about your weight if you are eating right (a carb restricted diet that avoids highly processed foods) and have good activity levels. The weight will come off over time. If you really hit a plateau of 2 months or longer - and research shows that plateaus tend to occur at weight levels that were maintained for a while during the periods of weight gain - the way to break through is by cutting back on the carbs rather dramatically: get your carbs only from 3 or 4 cups of salad for about two weeks and then resume a more sensible carb restricted diet. You will break through and resume losing weight.
