1. Physiological: This is relatively easy. The key is to understand how to get an accurate account of incoming calories and an accurate count of outgoing calories. When you have an accurate count of those you can lose weight. Andrew Huberman is really good on this: https://www.youtube.com/watch?v=GqPGXG5TlZw&ab_channel=Andre...

I say this one is easy because it is very easy to be misinformed about food. For example, someone may have heard that salads or protein bars are low calorie and healthy, but that isn't necessarily true. And once they realize that they can adjust their food intake to account for accidently over eating.

2. Psychological: Generally speaking, a lot of people with drug, alcohol, or food problems are dealing with some sort of stress, anxiety, depression, or childhood trama. Everyone has a limit to their will power. So even if you strengthen your will power if there is another force acting against that will power it will win and you will stress eat or stress drink. Depending on this situation, Therapy, Meditation, life changes, rehab can help.