# Help me understand this weight loss/gain phenomenon **URL:** \ **Category:** In My Humble Opinion\ **Created:** [April 15, 2021, 3:59pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086 "2021-04-15T15:59:25Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![Nature\_s\_Call](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nature_s_call/32/19006_2.png) [@Nature\_s\_Call](https://boards.straightdope.com/u/Nature_s_Call)\ **Post date:** [April 15, 2021, 3:59pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/1 "2021-04-15T15:59:25Z")
I (re)started a health kick last October - eating right and exercise. I’ve lost 50lbs. Yay me! When I stay disciplined, the weight comes off. Nice and gradually, a pound here a couple pounds there. But a week ago at my brother’s birthday I ate more than usual - far less than I used to but more than I have recently. I also neglected my run that day. The next morning my weight went up 5-6 lbs! I’m still today above where I was before that day. I had a similar experience at New Years, and again at the celebration of a friend’s anniversary - eat a bit more on one day and I’m rewarded with a large/instant spike the next day. I did not eat 5-6 lbs of extra food. Where did the additional mass come from? I presume the air - but that much still surprises me. Before my health kick I didn’t watch what I ate - and I ate a lot. My weight never changed that much for years. Now that I am near my goal weight, one lapse and bang 5-6 lbs in one day!??!! I’m in this for the long-haul, so to a certain extent I’m not worried what happens on one day or even a couple weeks. I’m also not surprised the first 50 lbs lost was far easier than the next 10 lb will be. I just don’t understand how one meal can have such an instant and dramatic impact, and take so long to “erase”. What is different about my slimmer body to make it react this way? Do you have any advice how to avoid such significant one-day increases, or is the answer “that’s what you get for even one undisciplined day - this is your life now”? ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [April 15, 2021, 4:04pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/2 "2021-04-15T16:04:41Z")
Might be water. Most of our body weight is water, not fat or muscle, anyway. My WAG is that with the additional food you ate (which, you point out, wasn’t 5-6 pounds,) it may have caused your body to also retain some more water as well. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [April 15, 2021, 4:06pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/3 "2021-04-15T16:06:48Z")
Yes, my guess would be temporary fluid retention. If you not only ate more than usual but also saltier than usual your body might demand more fluids/pee less fluids for a short period of time. A gallon of water weighs eight pounds. If you ate, say, two pounds more than usual and your body said hey, we need an extra quart of water for processing purposes that could be 4 pounds right there. I’m not saying that is the precise cause here, but water does have weight and our fluid balance does fluctuate a bit. ---
**Author:** ![filmore](https://avatars.discourse-cdn.com/v4/letter/f/7993a0/32.png) [@filmore](https://boards.straightdope.com/u/filmore)\ **Post date:** [April 15, 2021, 4:11pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/4 "2021-04-15T16:11:49Z")
Do you happen to have an idea of your normal “evacuation” schedule? Your body may be taking a bit more time to process everything and things may be moving slower through your system. It could be that the extra weight is in the cargo hold waiting to be shipped out. ---
**Author:** ![Nature\_s\_Call](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nature_s_call/32/19006_2.png) [@Nature\_s\_Call](https://boards.straightdope.com/u/Nature_s_Call)\ **Post date:** [April 15, 2021, 4:18pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/5 "2021-04-15T16:18:28Z")
@Velocity , @Broomstick Thanks for the quick replies. Retaining water - Does that mean my body is saying “Whoa, that’s a lot of food! Kidneys, don’t let that water go - we’re gonna need it.” If so, I guess before I lost the weight, my weight didn’t fluctuate because it kept the more-or-less same amount of water around to handle the constant barrage of McDonalds I threw at it. And the reason it’s taking so long to “drain” is because my body is saying, “we’ll just keep the tank full until we see this isn’t the new normal.” Is it still anthropomorphizing if it’s my body I’m talking about? ---
**Author:** ![Velocity](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/velocity/32/18006_2.png) [@Velocity](https://boards.straightdope.com/u/Velocity)\ **Post date:** [April 15, 2021, 4:20pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/6 "2021-04-15T16:20:38Z")
I wouldn’t worry about any small fluctuations in a short time. In any given day, the human body’s weight can vary within a 5-pound range, all because of water being exhaled and lost or sweated, or drunk, and food being consumed. TMI warning: Out of sheer morbid curiosity, I used to be in the habit of weighing myself before and after I peed, just to see how much weight the fluid was. It was often over 1 pound. You should only concern yourself with big long-term trends, such as gaining or losing 50 pounds over a year - things like that. ---
**Author:** ![CairoCarol](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cairocarol/32/3825_2.png) [@CairoCarol](https://boards.straightdope.com/u/CairoCarol)\ **Post date:** [April 15, 2021, 4:23pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/7 "2021-04-15T16:23:33Z")
Whatever it is - and I agree that water is the obvious answer - you aren’t alone. I’ve successfully lost weight a couple of times (just 10 or 20 lbs) and am amazed at how much weight can fluctuate in a day’s time. In fact I’m trying to lose my “Covid 15” right now and was dismayed the other day when despite eating modestly and exercising the day before, my weight shot up by two and a half pounds. But I got to thinking about what I’d consumed the day before and realized that I’d snacked on both olives and miso soup - excellent choices from a low-cal perspective, but very salty. ---
**Author:** ![Nature\_s\_Call](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nature_s_call/32/19006_2.png) [@Nature\_s\_Call](https://boards.straightdope.com/u/Nature_s_Call)\ **Post date:** [April 15, 2021, 4:23pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/8 "2021-04-15T16:23:46Z")
@filmore Interesting - I hadn’t noticed much difference in “schedule” but I’m not really paying that much attention. TMI alert: I do notice, though, that my bowlfuls of solid stuff are **way** more voluminous now on healthy food than when I ate junk. I don’t remember the last time I’ve had diarrhea (which used to be very common) - and often I actually fill up the hole at a sitting, requiring some plunger manipulation to successfully flush. That’s during periods of disciplined eating/exercise. Perhaps that extra volume is slowed by the extra digestion required. In addition to water retention, that all makes sense. ---
**Author:** ![MoonMoon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/moonmoon/32/2959_2.png) [@MoonMoon](https://boards.straightdope.com/u/MoonMoon)\ **Post date:** [April 15, 2021, 4:28pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/9 "2021-04-15T16:28:07Z")
Yep, water and waste. And, depending on how low your daily calories are to sustain your current weight, your body might be reacting in starvation mode. It’s the reason people put weight back on much faster than they take it off. Your body thinks, “Oh sh!t, I’d better hold on to every bit of this in case we starve again.” ---
**Author:** ![CairoCarol](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cairocarol/32/3825_2.png) [@CairoCarol](https://boards.straightdope.com/u/CairoCarol)\ **Post date:** [April 15, 2021, 4:28pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/10 "2021-04-15T16:28:16Z")
I also recall reading somewhere - sorry, I think it was on a men’s health site but I can’t remember where - that if you are doing mostly low carb and then one day have a lot of carbohydrates, your cells will react to the infusion of carbs by becoming more hydrated. No idea if that’s legit or it’s pseudoscience, but it does match my experiences. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [April 16, 2021, 12:04am UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/11 "2021-04-16T00:04:47Z")
Ding ding. Every gram of glycogen (the body’s form of carbohydrates storage) gets packed with 3 to 4 grams of water. Required. If carb depleted then a significant carb containing meal will lead to surprising weight gain by that mechanism. ---
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [April 16, 2021, 2:52am UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/12 "2021-04-16T02:52:00Z")
Could be trading fat for muscle. Muscle weighs more than fat. ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [April 16, 2021, 3:26am UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/13 "2021-04-16T03:26:05Z")
> [@Jinx](#): > > Could be trading fat for muscle. Not five pounds’ worth in one day, I don’t think. The previous posters’ suggestions of short-term fluctuations in fluid and bodily waste levels seem far more plausible. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [April 16, 2021, 12:04pm UTC](https://boards.straightdope.com/t/help-me-understand-this-weight-loss-gain-phenomenon/940086/14 "2021-04-16T12:04:34Z")
> [@Jinx](#): > > Could be trading fat for muscle. Losing fat and gaining muscle are two separate things; there’s no trading.