but if you overeat the rest of the time also no use.
let's do some simple math:
assuming you're 1.7m tall and 70kg and hardly exercise.
your daily caloric requirement to maintain your 70kg weight will
be about 1,700 calories.
to lose weight, you'll have to eat at a caloric deficit for a
sustained period of time. the maximum safe caloric deficit is 500
calories. any more than that will be harmful.
now, if you eat at a 500 calorie deficit for a week(1,200
calories daily), your weekly caloric deficit=3,500 calories, which
will translate into roughly a 0.5kg weight loss.
I think your dinner plus the ice cream is already about 1,000
calories.
also take note that as you lose weight, your daily caloric
requirement will also drop.

where to find the tables of food vs calories thingy?