An interesting thing happens when one starts burning stored energy.
(An aside, stored sugar, in the form of glycogen, will always get used first.)
To express this in the most general way: there are products, and by-products of the process of using stored energy. One of the products is water. This happens in two ways. For one, I've heard it said that when 1 gram of sugar is stored, 4 grams of water are stored along with it. For another thing, some of the oxygen we breathe ends up as part of that water during the "burning" process.
Some people will shed this water right away, others hang on to it longer. This is dependent on lots of things, like body type, metabolism, and diet.
If a person is on a high-carb diet, for example, a lot of that water gets stored again, along with the sugar. If a person eats a lot of salt, water is retained to keep the salinity level at optimum. And so forth.
Water weighs more than fat. When a person burns fat, the weight reduction shows up on the scale only after the water is excreted.
And this is one reason why it often takes several days to show a difference on the scale.
A chemist could explain this more clearly than I can.
| current weight: 248.0