Is 160 lbs too much for an 11 year old girl?

Depends on height &: maturity level. A weight of 160 pounds is appropriate for a mature female that is about 5'7" or taller. Girls usually grow 1-3 inches after starting their periods and reach final adult height within 1-2 years. Some girls have already gone through their growth spurts by 11, some have just started, so depending on this, it will give you a better idea of what's healthy for you.

Weight: Dies she have any past medical history including any chronic health issues? If not then according to the CDC growth chart, 160 lbs in a female 11 y/o falls above 95th%ile which is abnormal weight gain, category. Her ideal weight should be between 65 lbs and 105 lbs ( between 10th. &. 85 th%ile). Eating healthy, 2-3 times weekly strength training and endurance building can prevent health problems

Yes: If this kid is any shorter than 5'8" she is considered obese by standard charts & overweight if she is less than 6'1". Time for a good evaluation by her doc.