I'm sure many of you have heard this bashed around a lot when it comes to losing weight or in fact gaining weight.
It's the idea that when you eat after 6pm your body doesn't have the time to use the carbs as fuel before you go to bed.
When you're losing weight, you're in a calorie defecit.
Therefore if you're expending less than you are consuming, it really doesn't matter the time in which you eat carbohydrate based foods as long as you are achieving a defecit.
If my requirements for achieving a daily calorie defecit are 1800 calories for example:
I've had 1500 calories before 6pm, eating the remaining 300 calories whether they're predominantly carbs or not after 6pm you're still going to hit 1800 calories which keeps you on track for weight loss.
If eating carbs of an evening leads you into a calorie surplus (consuming more than you're expending) then you may quite possibly gain weight, but again that will be due to the actual surplus of calories you're consuming, and less likely due to the time of day in which you've eaten them.
There's research to suggest that you may even get a better nights sleep after consuming a carb based meal an hour or two before bedtime.
I actually practice this myself, by having a bowl of porridge, with cinnamon and blueberries an hour or so before bedtime.
Don't watch the clock!