Are you eating enough?!?

Bodies are very adaptive. If you eat less, they will down regulate and use less. Guess what happens when you go away for the weekend and give your body more? It will cling on to every single little bit that is on top of your normal patterns.

If you regularly feed yourself enough food (not living in a deficit) this doesn't happen. When your body gets enough routinely, your body trusts that more food is coming and can to let go of what it doesn't need.