Well, I only want to say that include fresh green vegetables in your 12pm meal. Eating green vegetables whether as salad or in boiled form is very effective control weight gain and be healthy in long run.
Take high protein supplements, and reduce your daily fat intake. For this purpose use the foods that contain high protein and very low fat. High protein would build up your muscles strength and low fat will keep your overall body weight in control.
My suggestion is to do backward bending and stretching exercise. Stretch and pull up your bell abdominal muscles that produce such lines. Hopefully it would tighten your skin and remove that fold lines.
Take high protein supplements before workouts because its good to boost up the fat burning process. I want to suggest bicycling for flattening belly and getting six packs fast. Along with your routine exercise you should consider bicycling, or use stationery bike for that. Bicycling is effective...
Yogurt has enough protein but not comparable to meat. So here are some other good sources of protein if these are available at your campus then you should consider them ...
Egg,
Mushroom, Peas, Spinach, Broccoli, Chickpeas
Nuts and Beans
Pullups would be best for your shoulders. Try pullups while carrying some weight on your back, it would add an additional benefit. Use as much weight as you can.