Obesity and its impact on health

would like to answer the following questions:
Does the obesity effect the human health?
Is obesity a hereditary?
Does the fast food increase obesity?
Do you think stop doing some sports is the main reason to have obesity?

i did a survey recently and asked questions including the one above. will attached results for your reference.

kindly make sure you include some statistics and reference of studies.
including reference at end is a must