How long after a bad day or few days does it take for the weight to show on scales?

[RidingSixWhiteHorses]

So if I have a good couple of days the weight loss according to the scales is pretty instant. Eg eat low carb and sugar for two days - lose a half a pound by next day. So if I have a bad day eating carbs and sugar how long would it take for that to become fat and show on scales too?

It depends, what do you consider to be a bad day? Because you would have to eat a LOT to put a pound of fat back on. If you have a bad day on the carbs, if you're usually low carbing you might show the next day or the day after, but it'll be fluid. The best thing to do is flush out the bad day with heaps of water and go straight back on the wagon.

it takes 3500 calories in addition to your daily expenditure to make a pound of fat so if you consistently take in an extra 500 cals a day for 7 days you should see it sometime the next week?

the scales are

the scales are what? Fickle? Blunt? Of very limited use?

I don't think it's an exact science. You can try to link weight directly to calories, but in my experience it isn't borne out on the scales. Eg sometimes you have a bad couple of days that's not reflected in your weight, other times you are really good but don't see a loss.

For me, the answer is to focus on what I'm eating and trust that in the medium term I will see the impact on my weight, but not worry about what the scales say on a day-to-day basis.

It takes a while for the body to lay down fat.

If I eat too much for two weeks over Christmas I'll gain around 6 lb
but its not fat
its water and undigested food
as I can get rid of it all in three weeks of very careful eating

undigested food and retained water can weigh a lot