You are not a failure. Here's why.
/If 90% - 98% of a particular smartphone failed to work after a few months, would you believe it was a problem with the phones or with the users?
If 90% - 98% of diets failed to "work" long-term, would you believe it was a problem with the diets or with the dieters?
The truth is that those statistics are accurate for diets. (I don't know about for smartphones.)
This video shares a few more truths (some of them scary), as well as a solution that actually does work. I'll tell you how your body and mind were created to function best.
Watch it and then let me know your experience with diets. (Your smartphone? I wish I could help you with that one.)