I'm on a homely diet since april : low fat, medium carb & veg protein. low on ani protein, no red meat, no fast food, greasy/fried food. high veg, fruits. brisk walking. i lost 13 lbs in this tenure. is this normal loss or i am seriously ill inside?

Let's see ....: It has been about 12 or 13 weeks since the middle of April (today is July 20). That would be losing about a pound a week. Now I don't know if you are trying to lose weight, but if you are, this is just about perfect! (I don't know if you worried that you are losing too much or not enough). But losing 1 pound a week on a sensible diet such as this is your best shot at normal long term weight.

Normal : A healthy goal is to lose one pound per week. Since April was 11-15 weeks ago, you seem to be right on track. Great job!

Weight loss: 1-2 pounds per week is the recommended healthy weight loss pace, but be careful with the quantity of fruits and grains you eat daily. People doing this kind of diet have a tendency to eat to much fruit or grains which has high sugar and carbohydrates content and this can decrease the weight loss pace.