Weight loss confused

Patient: I have recently lost 35 lbs over the last four months. I was a heavy drinker and was not really not active at all. My diet consisted of unhealthy high calorie foods (2500 calories). I started going to college and walking about 5 miles a day, 5 days a week. I severely cut back on drinking, and changed My diet to about 1400-1500 calories a day. I also started eating Non-red meat and mainly salads. Should I be concerned about the weight loss?