"what possible reasons could there be for weight gain from 55.6kg to 57.5kg while her body measurements have stayed the same?"
- her diet has not changed during this time (clean whole foods)
- she's remained active doing regular cardio and weight training
OK., assuming that her weight gain was gradual, then the combined effects of maintaining good diet and exercise may have improved her bone density, which would contribute to 'modest' weight gain. (I have yet to find more precise data on how much weight gain it can account for, but I expect that would also be influenced by personal genetics.)
Contributing factors:
- continuous exercise can increase strength and density of women's bones as well as increase overall bone mass.
- a woman's bone density is expected to peak in her late 20s. (and I am assuming she is about your age, which your profile lists at 26)
- increased bone density this could be a factor in why the weight gain stays on, since it does not fluctuate at the same rates as fat or muscle.
While this may not account for the total amount of weight gain it would be a contributing factor and supports her finding that the weight stays on - without increasing her body measurements.
I sincerely hope that you found this helpful.
She may also be encouraged to know that increased bone density will help her keep her figure as she gets older.
Cheers, and good wishes to you both.
- Acorn
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Data SourcesIf you or your girlfriend are interested in reading what I found on this topic - here are some of the books where I found the data and links to where they can be read online:
Topic: Women & Exercise increasing Bone DensityPage 9 of Strength training for women By Lori Incledon - Increased Bone Density
http://books.google.ca/books?id=UoG_zI6SYiwC&printsec=frontcover#v=onepage&q&f=falsePage 352 of Strength and power in sport By Paavo V. Komi, International Federation of Sports Medicine
http://books.google.ca/books?id=qScBYCPbWkcC&printsec=frontcover#v=onepage&q&f=falsePage 232 of Exercise and sport science By William E. Garrett, Donald T. Kirkendall - Growth and Peak Bone Mass
http://books.google.ca/books?id=Cx22TcXodrwC&printsec=frontcover#v=onepage&q&f=false