Weight/bf % scale reading trends

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Spitspot81
Spitspot81 Posts: 208 Member
in Health and Weight Loss
I have had the Fitbit scales with weight/bf measurements for over a year now, I use it purely for trend rather than accuracy .

Now my weight and bf% always seems steady until, like the weekend just gone where I end up having a little binge .... pizza, chocolate etc. I always find that after a weekend like this my weight shoots up by a couple of lbs but my bf% drops.

I have researched to find the reasoning behind it but fail to find much. Is it down to excess water being carried? Normally after a few days of regular eating the weight creeps back down and the bf back up again.

Maybe I should have a binge more often as a lower bf% would be ideal

Replies

  • AnnPT77
    AnnPT77 Posts: 32,737 Member
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    Think about the math.

    Pretend you weigh 100 pounds and have 20% body fat. That's 20 pounds of body fat.

    Now you add 10 pounds of water only. You weigh 110 pounds. You still have 20 pounds of body fat. But it's now 18% body fat, because 20 divided by 110 is 0.18 (rounded).

    If you added 8 pound of water and 2 pounds of fat (instead of 10 pounds of water), your body fat % would stay at 20% (because you'd have 22 pounds of body fat and 22 divided by 110 is 0.2).

    Not that those are realistic numbers, and not that the scale is necessarily that accurate. ;)

    Make sense?
  • Spitspot81
    Spitspot81 Posts: 208 Member
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    That makes perfect sense, thanks. So, would a little binge of pizza etc, when normally a balanced diet is consumed cause water weight gain?
  • Nony_Mouse
    Nony_Mouse Posts: 5,646 Member
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    Spitspot81 wrote: »
    That makes perfect sense, thanks. So, would a little binge of pizza etc, when normally a balanced diet is consumed cause water weight gain?

    Yes, though it's not the pizza, it's the carbs. When you're eating at a deficit you're usually at least a little glycogen depleted. When you eat a higher than usual amount of carbs, your glycogen stores are replenished, and each gram of glycogen has something like 2-3g of water attached to it. This is also why some people think carbs make them gain weight, because the scale will be up after having a carb-heavy meal. It's not fat, it's water (and there's a limit to how much glycogen-related water you can hold, because there's a limit to how much glycogen you can store).
  • Spitspot81
    Spitspot81 Posts: 208 Member
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    Nony_Mouse wrote: »
    Spitspot81 wrote: »
    That makes perfect sense, thanks. So, would a little binge of pizza etc, when normally a balanced diet is consumed cause water weight gain?

    Yes, though it's not the pizza, it's the carbs. When you're eating at a deficit you're usually at least a little glycogen depleted. When you eat a higher than usual amount of carbs, your glycogen stores are replenished, and each gram of glycogen has something like 2-3g of water attached to it. This is also why some people think carbs make them gain weight, because the scale will be up after having a carb-heavy meal. It's not fat, it's water (and there's a limit to how much glycogen-related water you can hold, because there's a limit to how much glycogen you can store).

    That is so informative, thank you for taking the tome to explain that to me. I really did eat a lot of extra carbs at the weekend....but in truth they tasted sooo good

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