Maybe make some small healthy choices that you can happily live with. Maybe it will not help in the loss department initially but will improve your nutrition and self esteem in the will power and being pleased with yourself for small achievements area. Then if you wish, move onto more from there.
When my kids were younger cleaning their room up was just so overwhelming for them as a whole, so I suggested just do under the bed, that got achieved then..how about that bit there.
I recently had a talk with a son who is now 25 and has a seemingly overwhelming situation, some he can change, some he can't. I brought back the cleaning room analogy and he found that by tackling a portion of his problem at a time that it is not so overwhelming.