College student diet/weight loss?

As much elliptical work as you can do. Since you are a woman (I presume), you probably don't want to and will not build much muscle. The main concern for men is that they don't do cardio because they don't want to lose hard-earned muscle. Cardio is still the single best EXERCISE for weight loss (diet is the single best thing for weight loss but cardio is the best exercise). Consistency is the single most important thing. As a college student, I know how hard this can be. You don't want to be a "weekend warrior" or do 6 days of exercise one week and then 2 days the next. Schedule at least 2-3 intense workouts a week and if you have time, just toss in a light work out here and there. As for core strength, don't do crunches or sit ups. Plank, hold your legs 6 inches from the ground while lying on your back, and Russian twists are great. Motionless core work outs are the best for stability and strength.