Can anyone explain child centiles to me?

[olivewreath13]

AIBU for thinking it's really confusing, or am I being thick?

I've been diagnosed pre diabetic this week and trying to overhaul my diet and tackle my weight as it's got out of control.

Youngest DC is also looking quite chubby. I'm trying to work out their BMI but everything gives me a weight centile, which don't seem to take into account their height? But their height must be a factor?

There’s charts for both by age. Obv a child on the 90th centile for weight and height is different to one on the 25th for height and 90th for weight.

You can use the NHS BMI calculator that takes account of height and weight and tells you their centile

Here's the charts used by U.K. health professionals

https://www.rcpch.ac.uk/sites/default/files/Boys2-188yearsgrowthhchart.pdf

www.nhs.uk/live-well/healthy-weight/bmi-calculator/

https://www.rcpch.ac.uk/sites/default/files/Boys2-188yearsgrowthhchart.pdf

The BMI calculator takes into account both their weight and height and tells you if they are a healthy weight for their height. So two children could weigh exactly the same, but if one is tall and one is short, the tall one could be underweight the short one could be overweight.

If you could tell us your child’s weight and height, we can tell you if they are a healthy weight according to the NHS.

Take 100 children of exactly the same age, and the same sex.
If your child is on the 90th centile then 90 children will weigh less and 10 will weigh more.

Mainly with weight and height look at them together. If they are both a similar centile that's probably OK. If your child is the tallest, it wouldn't be surprising if they are also one of the heaviest. You may have a problem if weight is 90th but height is 50th.

Sorry cross posted with the poster above

NHS BMI calculator

The way I understand it: if your kid is on the 50th centile for height and/or weight, then in a room of 100 children, there would be 50 children who weigh less/are shorter and 50 children who weigh more/are taller than your kid.
Healthcare professionals then look at the height and weight charts together to see if your kid is in proportion. My middle child was a very poorly baby, and was on the 0.4th centile for weight for quite a while, but on the 50th centile for height. He was wildly out of proportion!

How does that work for tall kids though? I've tried looking at the chart thing, it suggests all kids over a certain centile for weight are overweight, even if their height is also over that centile?

Use this link, and it will look at height, weight and age (assuming your youngest is a child) and give you an indication of where they sit in a range of 100 kids.

In all honesty, if they are primary aged and look a bit chubby, a bit more excerise and some healthier food is probably a good idea whatever the charts say. Less clear if they are older.

The nhs calculator takes both height and weight into account. If looking at separate height and weight charts the important thing is that they are within two standard deviations of each other.

Ah ok. I was hoping the NHS one didn't take into account height 😳

In reality if, to you, as his parent think he looks “chubby” he’s likely overweight. It’s pretty difficult for parents to objectively critique their child’s weight.

Id recommend using the NHS bmi calculator posted, it’s pretty accurate, and take that as a starting point.

All my DC were well above the 98th centile. This is got height and weight so they are in proportion. It is when they don’t follow same pattern for both it is a problem.

What are the standard deviations? I think they just look a bit chubby, but the NHS calculator thing says very overweight 😬

Can anyone tell me if the standard deviations are the bits between the lines? So weight and height should both be between the same two lines?

www.rcpch.ac.uk/sites/default/files/Girls_2-18_years_growth_chart.pdf

If they are a very high weight centile for their age, they are almost certainly overweight regardless of height. Overweight children are often or usually high on the height centiles as well, because the calorie excess has caused them to grow more sooner; it doesn't mean they're actually "naturally" tall, nor is it a good thing.

Take your DC to the GP, but yes it sounds like they are overweight.

This is a good one OP to use in metric.

www.cdc.gov/healthyweight/bmi/calculator.html

99th centile is a big problem.

No, they don’t need to be the same venture for weight and height. Eg my 14 year old is tall and skinny for her age which means she is something like 91st venture for height but maybe 50th centile for weight. If it was the other way round, ie 50th for height but 91st for weight, she would probably be overweight.

If you use the BMI calculator, then the NHS has figured all that out for you, and if it’s saying “very overweight” then I’m afraid you do need to change your DC’s diet and get them moving more.

*centile not venture!

The correlation between weight and height isnt simple. A 90th% height child shouldn't necessarily be 90th% weight - taller children don't necessarily weigh a huge amount more. My 90th% height child is 65th% weight, which is quite normal. Also overweight children tend to gain height early, then stop growing and are left still overweight.

it suggests all kids over a certain centile for weight are overweight, even if their height is also over that centile?

Yes. Children basically shouldn't ever look chubby, they should be rather lean. Healthy, naturally tall children often have a weight % a little under their height.

She's showing up at the 98th centile. It's thrown me a bit because I really wasn't expecting it to be that high, she doesn't look that overweight to me.