My son is obese and I am so responsible

I applaud your honesty, as well as your wish to rectify the situation.

You should replace unhealthy treats with healthy/healthier ones instead.  Nuts (if he doesn't have an allergy to them) such as mixed nuts, dried fruit, fresh fruit (fruit salad might look appealing), low-fat cheese sticks, cucumber/pepper/raw carrot sticks with a low-fat houmous dip, change your bread and rolls to granary, always use half-fat or low fat cheese.  Health shops and maybe some supermarkets also do crisps made of beetroot and other sliced dried veggies.  If you get him involved in preparation he will probably show more interest in eating them than he otherwise would.  The bright colours of mixed fruit salads and the houmous and veg sticks should appeal to him.

You can also hide cooked vegetables in pasta sauces by blending them up if he's not eating enough vegetables.

Instead of using sugar, use Stevia granules in anything you would have with sugar.

Use low-fat milk or milk alternatives such as rice milk. soya milk etc. Cut all the fat off meat.

If he is using an adult sized plate cut down to a side-plate size so he doesn't notice his plate has smaller portions.  Don't cut portion size if they are already age appropriate though, in that case it's the content that needs to change.  This isn't about a diet it's about changing what he eats, unless medically advised by a health professional you shouldn't put him on a diet.

If he is boredom eating, ensure he is kept as occupied as possible.  As you have realised, if you don't buy the unhealthy foods/treats then no matter how much he wants them he can't have them.  He may meltdown at first, but he will get used to knowing what is available.  You could also try explaining to his logical mind, that unhealthy food is bad and there are nice-tasting things that are good for him.

Good luck.

I applaud your honesty, as well as your wish to rectify the situation.

You should replace unhealthy treats with healthy/healthier ones instead.  Nuts (if he doesn't have an allergy to them) such as mixed nuts, dried fruit, fresh fruit (fruit salad might look appealing), low-fat cheese sticks, cucumber/pepper/raw carrot sticks with a low-fat houmous dip, change your bread and rolls to granary, always use half-fat or low fat cheese.  Health shops and maybe some supermarkets also do crisps made of beetroot and other sliced dried veggies.  If you get him involved in preparation he will probably show more interest in eating them than he otherwise would.  The bright colours of mixed fruit salads and the houmous and veg sticks should appeal to him.

You can also hide cooked vegetables in pasta sauces by blending them up if he's not eating enough vegetables.

Instead of using sugar, use Stevia granules in anything you would have with sugar.

Use low-fat milk or milk alternatives such as rice milk. soya milk etc. Cut all the fat off meat.

If he is using an adult sized plate cut down to a side-plate size so he doesn't notice his plate has smaller portions.  Don't cut portion size if they are already age appropriate though, in that case it's the content that needs to change.  This isn't about a diet it's about changing what he eats, unless medically advised by a health professional you shouldn't put him on a diet.

If he is boredom eating, ensure he is kept as occupied as possible.  As you have realised, if you don't buy the unhealthy foods/treats then no matter how much he wants them he can't have them.  He may meltdown at first, but he will get used to knowing what is available.  You could also try explaining to his logical mind, that unhealthy food is bad and there are nice-tasting things that are good for him.

Good luck.