Wow, this has opened my eyes to some of the abuse some children have to endure. What fucked up adults you're going to rear. Why would you do that?
OP - when is he most hungry? That is when you should be giving him nutritious foods.
Dd always ate the bulk of her food in the first half of the day.
What is his breakfast typically? Lunch? When is he getting all the carbs? Hummus and bread at night is fine. Dd always persuaded her Dad to give her toast with chocolate spread at night. We knew it was a delaying tactic, but, it's the equivalent I suppose of the American cookies and hot chocolate.
Lidl's own brand 'Nutella' has a higher content of nuts than actual Nutella.
How about fish (grilled salmon?) or baked fresh cod/similar or something? Excellent source of nutrition.
At two, dd's diet would have been something like this.
Breakfast - porridge - those little individual sugary sachets from Lidl - do in microwave.
11am - a cheese string/yoghurt/banana - one of those.
12pm - lunch. Sandwich with tuna/ham/roast chicken/roast beef or a wrap with chicken and you can stick fresh spinach leaves/rocket/plain lettuce in for greens.
3pm - Dinner! So something like beef stew, chilli con carne, chicken casserole, fish, sometimes pizza, sausages, anything really
6pm - Our dinner and she'd eat a bit of that if she fancied it
Just before bedtime the toast with chocolate spread if she asked.
Smoothies often done with any combination of fruit/cranberry juice/yoghurt.
The bulk of dd's diet would really have been proteins. We would often have a salmon fillet each with side salad, sometimes noodles as she developed a taste for those at her childminders.
In terms of sugars, the chocolate spread and the sugar in the porridge in the am would have been the highest.
Was told to give proper yoghurt not petit filous as pure sugar more of less. Fruit was always offered but had to be given either via smoothies or half a banana, chopped up apple and sometimes things like tinned mandarins/pears/fruit cocktail or something.
With the fish, if he will eat (dd adored fish), if you dress the salad with just olive oil/cyder or white wine vinegar and a bit of salt, it compliments the fish well.
Casseroles/stews great at hiding carrots etc. Chilli could have tinned toms and peppers chopped up very finely.
You'll get there. He's not going to starve as he's overweight, but try to be more adventurous/nutritious when he's really hungry.
NO snacks such as icecream/chocolate/crisps. No need for them.