Change in % fat and muscle question

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Hey all, was just wondering if a 9% increase in body fat and 11% decrease in lean muscle mass is possible within a week???? That seems like a huge, negative change, and although I didn't have the best week ever, it wasn't bad either. I have exercised every day except one, and have been eating well. And that seems like a huge change in numbers for one week!!!! I used the same scale, mind you I don't really know if I am using it right because it doesn't belong to me and no one else was around when I went up and used it. But I don't see how it could give me an incorrect reading even if I don't know how to use it.

Acg67

unless you had a limb chopped off, prob not possible

BIA scales are notoriously inaccurate, hydration levels really screw with it among other things

Play_outside

LOL definitely still have all of my appendages. I was just researching how accurate they are and it seems there is no standard. So I think I will just stick with weight and measurements and how clothes fit.

Acg67

among other studies done on the accuracy of BIA scales

Changes in body composition during weight loss in obese subjects in the NUGENOB study: comparison of bioelectrical impedance vs. dual-energy X-ray absorptiometry.

Verdich C et al. Diabetes Metab. 2011 Jun;37(3):222-9.

"RESULTS:

At baseline, BIA significantly overestimated FFM and underestimated FM (by 1-3 kg on average) compared with DXA, and the limits of agreement were wide (mean ± 7-8.5 kg). "


A comparison of dual energy X-ray absorptiometry and bioelectrical impedance analysis to measure total and segmental body composition in healthy young adults.

Lehy S et al. Eur J Appl Physiol. 2011 May 26

"BIA was found to underestimate the percentage total body fat in men and women (p < 0.001). This underestimate increased in men with >24.6% body fat and women with >32% body fat (p < 0.001). Fat tissue mass in the trunk segment was overestimated by 2.1 kg (p < 0.001) in men and underestimated by 0.4 kg (p < 0.001) in women. BIA was also found to underestimate the fat free mass in the appendages by 1.0 kg (p < 0.001) in men and 0.9 kg (p < 0.001) in women. Compared to dual energy X-ray absorptiometry, bioelectrical impedance analysis underestimates the total body fat mass and overestimates fat free mass in healthy young adults."

healthybabs

That is most likely not possible. Alot of those scales have memory settings on them. For any chance of accuracy, you need to be sure you are using the scale correctly. As a side note, I have one and find that about every 5 lbs results in a little difference.

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Thank you!