It is perfectly doable - but I indulge sometimes. Pizza is my main vice, sweets second.
When I feel like losing some weight, I just lose the added sugar (e.g. no sugar in tea, no sweet drinks, sweets), stop with junk food completely, follow the old principle of 'breakfast of a king, lunch of a farmer, dinner of a beggar", go to bed at 10 PM sharp and leave half.
The last part basically means I eat exactly half a portion. I immensely enjoy eating, so I do not stop myself from rnjoying food - I just chew longer, smaller mouthfuls and basically trick myself into thinking I ate a lot.
I also share a lot - giving half a portion to colleagues that are out to lunch with me (before starting to eat).
At these points I go for quality instead of quantity. And eat a piece of dark chocolate once per day as 'reward' when I uphold all the rules, which works as nice conditioning tool.
Works miracles for me, last time I dropped my terrible results from checkup into normal in 3 months.
I may have to do it again as I started gaining weight again. I even got above 100kg. Something I told myself I never would.