The way I see it is this.

You start your days work sat on your arse and finish still sat on your arse only getting off it to fill up with fuel, take a shit/piss and eat etc.

Your body doesn't need large amounts of energy to just sit there pressing pedles and turning the steering wheel.

You still get hungry despite the fact you're not active and burning off this excess energy.

I have increased in weight over the last few years as I became a mobile auto electricial driving up and down the country for as much as 8 hours continuously on occasion.

Try eating foods with lower carbohydrates and instead of eating loads at once, eat less but more often. Also try drinking water instead of eating, or drink water with your meal.