Body Fat Overnight Gain

[MickyH]

Hi,

Just checking is it possible to gain 6lb of fat in approximately 12 hours.

Readings from my body composition scales;

Yesterday 176.2lbs 22.2% fat = 39lb fat

Today 175.8lbs 25.6% fat = 45lb fat

I am currently consuming 1000 cals less than I burn and think the Fitbit is probably overestimating my calorie burn.

I'm eating healthily and yesterday had plenty of protein. 

Thank you

[Dominique]

Scales that estimate (stress on estimate) body fat via the bioelectrical impedance analysis method are very sensitive to hydration. No way body fat can swing 6 pounds in a day, or even a week. I’ve always been puzzled when I see people reporting swings of 4-5% in BF% on a daily basis. I weigh every single day (always in the same conditions, first thing in the morning, after trip to bathroom) and within any given period of 2-3 months, BF% values are all within a 1.0-1.5%. For instance, during the past three months, the highest was 15.2 and the lowest 14.1:

I have two other scales (from Withings), with which I get similar results: a bit lower in absolute terms, but same kind of fluctuation range.

Maybe your dietary experiments (intermittent fasting, bullet-proof coffee etc.) are causing this... I tend to have a boringly regular and repetitive life: I eat more or less the same foods, spread across the day, my activity level is more or less the same everyday.

[Daves_Not_Here]

Admit it - you raided the fridge last night and mowed through an entire gallon of Rocky Road.

[MickyH]

Thank you for the reply. I usually weigh myself at the same time each day to get consistent readings but was keen to use the new scales to see what the variance was like.

I suppose I'm surprised and disappointed that the reliability and the accuracy of body fat readings on the new scales appears to be worse than the 12 year old set they are replacing.

I did a further reading a few hours later yesterday and I'd lost 3 lb of the fat?!

I've just done another reading frst thing this morning and I'd gained 0.2 lb in weight but lost 1.4lb in fat compared to the same time the day before.  I also expect it is unlikely this to be possible but it is what I'm trying to achieve as I'm happy with my weight but not the fat %.

However the skeletal muscle stats don't reflect an increase in mass so not sure what is going on and don't want to spend any more time doing calculations as I'm fairly confident the reading don't stack up. 

Im going to continue using them once a week going forward but take the readings with a pinch of salt and look in the mirror for improvements. 

[Dominique]

@MickyH: just curious: what brand and model of scales are you using? I have experience with smart scales from Fitbit (Aria) and Withings (now Nokia), and I’ve found them reliable/consistent.

[MickyH]

I got some by Yolanda. They were the highest rated smartscales on Amazon. 

They were about 1/3 the price of yours so maybe you get what you pay for. 

[Dominique]

@MickyH: I must admit I’m not familiar with Yolanda, though I did see the models on Amazon now you’re mentioning it. I was recently pointed to two reviews of bathroom and smart scales:

http://thesweethome.com/reviews/the-best-bathroom-scales/

http://thewirecutter.com/reviews/best-smart-scales/

Both outfits that did the reviews are part of the NY Times, but I don’t know if it’s a sign of reliability. Their picks (EatSmart and Eufy) were unknown to me.

For how long gave you had your scale? As I see it, even if you weigh daily, your best bet is to focus on long-term trends and not to overthink the daily fluctuations. This is why I like TrendWeight (see link in my signature).

With scales from Fitbit and Withings/Nokia, you pay partly for the convenience of having your weigh-ins automatically logged to your personal account, which gives you your full history without having to manually write them down.