Rapid weight loss/ Weight gain

I’ve just invested in some cheap and cheerful smart scales (Renpho £35ish off Amazon)
Weighed myself in excitement when I got them which was Wednesday night, after a large meal from Nandos.

My shiny new scales told me I weighed 93.2kg :frowning: this info hurt as I thought I was about 90kg…

I then weighed myself this morning after eating pretty clean yesterday (apart from my now daily mince pie) and I weighed in at 89.5kg!
Is this kind of weight gain and loss normal in people? Are poos really that big!?


My biggest weight fluctuation in a week was 97.1 Kg on Wednesday, eating a stupid amount of chinees food combined with a loud of fluids and waking up on Thursday weighing 100.4 Kg. So I decided to have a stupidly big ride and 3 poo’s. Weighing in at 97.5 on Friday.

So yea thing can change allot in a few days.
On a normal stable diet it usually is not tho. Try writhing it down for a few weeks and see what happens.
Also make sure the scale is on a flat surface and try not to move it around in the floor to much. That really messed with my weight data for weeks earlier this year.


Dont over look things like sodium intake, the resulting water retention in your musculature, and weighing yourself at a consistent time of day. Also take 3 measurements and avg. The scales are almost all using an electrical pulse and that can fluctuate between measurements.

Things like bone density should be pretty static.


Make sure you’re weighing yourself at the same time under the same circumstances if you want accurate comparisons. You said you weighed yourself after a meal at night vs in the morning. You will generally always weigh less in the morning due to dehydration and other factors. I’d recommend going forward to weigh yourself in the morning after you wiz and before you eat or drink anything. Then use that as a benchmark.

I’m 175-ish at the moment and it’s not uncommon for me to fluctuate a few pounds day to day depending on my workouts and quality/quantity of food.


I often deliberately weigh myself before bed, and then again when I wake up and can easily lose over 1 kg overnight from loss of water through breathing/sweat and urine.

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All very interesting! Never thought you’d lose so much water just from sleeping!

The general idea is to weigh in the mornings after using the restroom, always weigh roughly at the same time and dont be obsessive about ups and downs as your weight will fluctuate quite a lot. 3-5 pounds depending on food and liquid intake daily.

I hope you have a mattress protector on :wink:


Just for reference these are my weight trends over the past month.

These are all done around the same time of day and in as consistent a set of circumstances as possible. There are ups and downs but the overall trend is heading slightly downwards and that’s what matters.


Guessing that most recent peak was Thanksgiving :rofl:


We don’t have that holiday here in Scotland unfortunately. It’s frustratingly easy to spot the cheat days though!


I weigh myself every morning and can notice some fairly big weight fluctuations depending on what I eat/drink the day before. In general if I keep to my healthy diet/exercise it will go up or down ~300 grams. However if I have a cheat day (or 2) where I gain 1-3kg and then the following day I eat normally and do a ride I can see it go down by that same 1-3kg.

For a while I was also weighing myself before bed and then immediately after waking and using the washroom. I would see a difference of 800 - 1000 grams the following morning while I did that.

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@heppyhepz First guess - water loss :slight_smile: I will say that some of the grueling, 90 minute rides sneak in a TON of calorie deprivation. Just finished Leconte last night for ~1400 kCal drop. That crap adds up if you don’t replenish calories ASAP.

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The amount of stagnant feces in our body is between 1.8 to 5kgs for the average person, depending on the diet, hydration and bowel motility.
Source - google

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After 2 months that’s what you came up with, lol.


Wow. I weight myself once a month, if that. Yeah, I’m looking at smart scales now, but wow.

I dont know really, mine stuck at 70 kg ! -_-

One of my mates could easily drop a min 5kg water weight (she’s happier to think otherwise haha) after a weekend of mustering livestock.

Anyway this also reminded me of a topic I listened on a podcast some time ago. Apparently fat ‘loss’ takes a lot of huffing and puffing work! Obviously, but literally is breathed out.

“84 per cent of atoms that make up a fat molecule exhaled as carbon dioxide, and the remaining 16 per cent lost through water, excreted in bodily fluids such as sweat, tears and urine … Their analysis also showed that for every 10 kilograms of fat being ‘lost’ or oxidised, the body actually needs an additional 29 kilograms of oxygen, with the resulting output of 28 kilograms of carbon dioxide, and 11 kilograms of water.” https://www.abc.net.au/science/articles/2014/12/17/4149911.htm

i like the 3 measurements and take an average, great idea!