Just wanted to add this little bio to what the others here have already said. What you have been told IS correct, by the way.
Mrs. BE has lost 50-58 lbs, depending on the prior days carb intake and monthly cycle status...all without really working too hard! The first 15 lbs flew off using just the workout (if you want to call it that) you described, and eliminating just bread and most sugar from her diet. No heavy weights, no long periods of cardio, and no restricting calories from other foods. In fact, she probably replaced the bread and sugar carbos with 2x the calories from rice, beans, fruit, etc. Kcal intake was probably 2500-3800/day.
After plateauing (sic?) for two months, and reducing calories to no avail, we went in search of some help. A gym membership, cardio and machines five days per week started. For the first month we used every machine LIGHTLY, every day, for as many reps as our little muscles would go. (not many, by the way) She lost another 5 lbs in that month with no further diet modification. It took about a month to get acclimated to the machines they had, then we went to library and got some fitness/weight lifting for women books.
It was time to figure out exactly what we were SUPPOSED TO DO!! We learned how muscle recovery time helps workouts, that women CAN NOT get big from weights, and that more muscle will help increase metabolism while resting so that you burn more calories!! We also read a LOT about benefits of free weights and discovered that LESS CARBS and MORE PROTEIN/FATS were needed for her to lose much more weight!!! (Most of our kcalories came from grain, pasta, hidden sugars in juices, spaghetti sauces, and other prepared "healthy" foods.)
We changed our meals slightly, just so that cardio was first thing in AM before breakfast. We carried protein powder to gym with us and mixed a shake after workout, then drank it while doing 15 min low intensity "cool-down" cardio on the bikes. [We added creatine after a couple of weeks, but that was a waste because our workouts were not heavy enough yet.] After getting back home, we have eggs, oatmeal(plain), or fat-free sausage or maybe breakfast steak/chicken. We also almost always had a little of some type of 'low glycemic index' fruit with breakfast. We added a heavy protein lunch for most days, with dark green leafies and another small serving of fruit. Dinner was pretty much the same as lunch, except add lots of broccoli, cauliflower, and no fruit. Late evenings, about 45 min before bed we added another 'lite' protein only shake. Off came another 10-12 lbs. with relatively no effort.
Next came a simple, loosely defined workout routine that was EASY and COMFORTABLE. (If you don't have any workout books yet, get the second edition of "Weight Training For Dummies" for about US$10 at Costco or Wal-Mart. It isn't the best, but it is darn good as a reference for equipment and exercises alone.) She still didn't REALLY work out hard, this just added a method and routine that helped with getting consistent. Also, it helped with good form and not getting carried away with one exercise or body part. The routine was not the best split of exercises in the world, but it was a start. In six weeks, another 8-12 lbs came off. Constant, and consistent, improvements in workout technique and intensity have followed, as they became comfortable and possible. Nothing went fast except when we changed the diet, routine, or intensity.
That was about 2 years ago and we have discovered many things. Mrs. is VERY carb sensitive, so carbs were slowly tapered to less than 18% of diet over about three weeks. She now cycles carbs in a semi-random fashion so that her body doesn't think it's being starved, and there are carb refeeding days every 7-10 days. (We had cut her calories too much, and that actually limited her loses because she did not feel up to increasing intensity workouts.) We have tried ephedra and norephidren based fat burners with some limited success. Yohimbine and Flax oil have proven to be the best supplements other than protein. No AAS as of yet, but the BF% is still in the high teens, and she wants to be below 16% when starting. [Her two workout partners have had wonderful success with anavar and winny. But they both don't care too much about the sides, which they DO have.]
Her workouts are now more varied on the splits, but not still not perfected. The more developed muscle groups (thighs, glutes, and lats)are only worked every 10-12 days, weaker groups are worked ever fourth workout day. She has a minimum of 2 days for recovery between workouts of a muscle group, and the groups keep changing every few days along with the diet and carbs. [We are not as anal about this as it sounds, but when another plateau is reached, we keep tightening up slack here and there.]
Cardio has gone from 20 min. every day up to 50-70 min every day before breakfast. This probably made the most dramatic change of all! I can't stress enough the difference those minutes past 20 can make. This was a slow progression though, she didn't try and bump it up too fast. [You have to make sure you have enough calories in your diet to do 45+ min. cardio at 70% MHR without having your body go into starvation mode.]
Anyway, my point is that you should start slow and build on successes. If something doesn't appear to work after 3-4 weeks, try something different. We lurked here and over at AnabolicFitness.com for a long time, trying the various advise that was applicable. It is amazing how quickly your appearance changes when you start using weights properly. Even though your weight may increase, as Mrs. BE's did, you will have definition and tightness that wasn't there before and people WILL notice.
If you don't have a workout partner knowledgeable in women’s fitness, specifically weight training, hire a personal trainer for a few sessions every three or so months. It will be a very wise investment because women’s needs vary so greatly from men. Some would argue, but talk to those here with more experience and you will begin to pickup on the differences.
Good luck and congratulations on deciding to remake yourself.
BE