Science of weight-loss /gain - help me understand it please

[carabos]

I'm really struggling to understand how weight gain and loss actually works (i'm not stupid, just overwhelmed with conflicting info).

What I don't understand is how people can say on threads that they went mad at the weekend and bust their diet, then weighed in on Monday and found they'd gained a couple of pounds which didn't surprise them. Well it surprises me, because I don't know how, if it takes 3500 calories to make a pound of fat, that you could a)eat enough extra calories over a weekend to make a couple of pounds of fat and b)how it could turn into fat that quickly.

Any science-y types able to explain? And why doesn't it seem to work in reverse i.e. as soon as you've dropped the extra calories, you don't immediately lose weight?

I'm no science-y type, but I have noticed that the actual weight of the food itself makes a difference, which isn't hard to understand! If I weight myself when I get up, then drink 2 cups of tea, I have immediately "put on" a pound. Obviously it's just the extra fluid. If people eat a lot of food, then they will appear to be heavier the next day (until you get rid of it).

That's my theory anyway.

I think that trying to understand everything is the quickest route to madness!

We all understand the basic calories in, calories out balance is what counts but there are so many ways that are supposed to boost it and, once you add in the psychology of weight loss, the whole thing is mind blowing!

I have a thirty year history of dieting, I am supremely knowledgeable about diets and weight loss yet I am still fat, in fact I am now fatter than I have ever been before!!

I am now just trying to focus on health and not over-think it

Crappy food is often high in salt, which makes to retain water. So a weekend binge will temporarily cause a lot higher gain than it actually does (so a few days later the scales will be lower even if you were eating at maintanance).

Essentially quite a lot of that extra weight is water (usually around 50% at least).

I think eating carbs and salt causes water retention hence ability to gain 5 pounds over weekend and then able to lose it within a few days. Plus eating lots of food adds weight until it all comes out as well!