Foam in the urine. Anyone help me out!

From past 6 months I was getting foam in my urine i gone to the hospital and got check ups for protein in my urine and all the checks required for kidney and blood tests, twice in 4 months, but it turned to be nothing in both the tests, but my foam in the urine was continuing this making me not to take proper diet where I read on the internet that eating more meat & certain foods can lead to damage of kidneys so keeping that in my mind i stopped taking many foods which results me becoming thin, i had lungs air way allergy my doctore was saying may be due to that it may be causing foam in the urine, except getting foam there is nothing illness in me and my tests where also normal and healthy as said by my doctor, can anyone help me out regarding the same.