Have you ever consumed a lot of "junk foods" on the weekend then step on the scale and the number that jumps out at you is a few pounds (or in our minds A LOT) higher than before you had a glorious weekend full of delicious foods? Or, alternatively have you ever restricted your calories to lose weight, and after a week or two you weight yourself and the number that you see makes you smile because it went down a few pounds and you think "YES it's working!"
The same thing is happening in both these cases. The weight you have either put on or lost according to the scale is water weight. What is water weight? Well, 50-60% of your body is made up of water. This percentage fluctuates depending on our eating and lifestyle habits.
If you eat a lot of salt, your body is going to retain water or to be super specific your cells will retain lots of water. Just like a diet higher in sugar will spike insulin levels which can translate to your body holding onto a lot of sodium, which then domino effects into the body holding onto water. Another reason is carbohydrates. For every one gram of carbohydrate your body stores 3 grams of water, so if you carb it up, you may feel "heavier" than you did pre-carbs. Don't worry though, this is completely normal!
Here's the deal, when you restrict calories, your body will burn through the restricted calories that you are consuming and then it will head for your glycogen stores (your body breaks carbs down into glucose which is stored in your liver as glycogen and later used as glucose for energy). Glycogen is bound by water, remember 1:3 ratio. So when you burn your glycogen you simultaneously let go of the water that comes with it, bingo we have water weight being lost! 8-10 pounds of the weight you will lose via calorie deficit will be water weight. Alternatively, if you eat a lot more of the foods you don't normally eat, things like pizza, burgers, poutine (a Canadian staple!) - all that yummy goodness, you then retain more water, which can leave us feeling not so good because we feel like we have gained weight.
Let me be clear, retaining or losing water weight is NOT the same thing as loosing or gaining fat. Don't worry if you eat a bunch of food you "don't normally eat" and step on the scale, that number will come down in a day or two. Or alternatively when diets promise you "fast weight loss in 10 days", "Detox and cleanse to lose weight" or "drop pounds by the day" they are scamming you because it's all just WATER WEIGHT, not actual fat. I mean hey, if you just want to be sad that you can't enjoy specific foods on one of these diets, go for it, but just know that you are just moving around water.
What does work? Ditching the scale because the number shouldn't dictate how you feel. Eat in a way that feels good to your body and don't worry about feeling a little heavier or lighter after a meal, it's just water!