You can reduce the irritation of rubbing by wearing gym compression shorts.
Weight loss is only 10-20% exercise and the rest is food intake. Reduce portion sizes, cut down on between-meal snacks and eliminate sugary drinks (including artificially sweetened ones).
To start with every time you feel like snacking.......Do something to occupy your hands and mind.
Drink a glass of water BEFORE eating a meal.
But mainly do something to occupy yourself and take your mind off food and eating.