Remember that exercise is a double edged sword for weight loss. Exercise will make you feel better, and increase your energy, and your sense of well being. But exercise will also decrease your metabolic rate, and make you hungrier, so it can slow down your weight loss. Walking is fine. But 45 minutes of cardio is probably not in your best interest, because of the metabolic downshift after prolonged exercise. The exercise that I recommend is four 3 minutes intervals, every other day. Exercise as hard as you can for 3 minutes on a treadmill, elliptical, stepper, etc. Recover for 1-2 minutes. Do this 4 times.